The CNC challenge, a different sort of mod
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LBRC
- bitGangsta'
- Posts: 361
- Joined: Sun May 02, 2004 1:25 am
- Location: North West
- Contact:
The CNC challenge, a different sort of mod
Noticed that Color0 is picking up a CNC mill so I thought I’d start a thread, have been using a small Taig
while I work on getting one that will hopefully do what I really want.
Santa Please: Haas OM-1A
Office Mill; 8" x 8" x 12" (xyz), 5 HP, 30,000 rpm ISO 20 taper spindle with 20 tool carousel, includes Visual Quick Code, 1MB, Beacon Light, coolant pump, high-speed machining, etc.
At a buck under $45K it’s sadly just a little out of my price range so it’s time to mod something
The challenge is to make a home desktop mill that will let you do the same type of precision micro work without robbing a bank first. Enter the Xmod mill otherwise known as the Seig X2 Mini-mill sold by Harbor Freight, Grizzly, and others.
At around $500 the Seig has a great price tag but as far as precision marching goes its pure slop, and even worse it’s manual. However as a solid piece of iron for the foundation of a DIY CNC retrofit project it’s darn near perfect.
I actually started my CNC adventure last year but soon discovered that like modifying micro/mini RC cars sometimes what you order is exactly what you get but not always what you really needed.
Definition: Backlash - play or lost motion between loosely fitting machine parts.
That’s the real enemy, a Seig X2 mill can have up to 0.1” of backlash in the X & Y and I don’t’ even want to think about the Z axis slop. The little Taig CNC desktop mill, approx. $2.3K as a turn key CNC mill, I’m currently using has around 0.02” which although an improvement is far from the ideal since a critical eye can detect discrepancies down to 0.001” and even that can be too much for perfect fitting micro car parts. So basically I want a mill with effectively “0” measurable backlash.
The backlash fix starts with ball screws but like modding our cars success depends on choosing the right parts and how you install them. I needed/wanted that zero backlash ideal but it turns out that most of the ball screw Seig X2 turn key packages and kits although nice and a great price are in what I call the Xmod class, great for making small display panels, 2 to 3 inch parts, and other home CNC projects where a high degree of precision isn’t exactly necessary but not something that will let you compete on the tack with a Mini-Z in other words not precise enough for the micro mini car parts I wanted to make. Most use inexpensive rolled ball screws with lead errors of up to .004 inches per foot along with single ball nuts so that they can still have as much as .02” of backlash making them no more precise than a Taig or Sherline at best.
The simple solution would be precision machine ground zero backlash ball screws with high quality zero backlash ball nuts, but again the price!!! Parts like those are why that Haas costs $45K. Never fear there is usually always a solution you just need to know what it is and why you need it, simple really go for high end rolled ball screws that have a minimum of 0.001” of lead accuracy some are now available at affordable prices that actually exceed the quality of low end machined ball screws, then use two apposing ball nuts so that you can tighten them against each other sandwiching the ball screw threads between them and eliminating the backlash. Takes more room and requires modification of the mill frame itself, along with doubling the cost which is why it’s not popular as a turn key kit or package but in the end can achieve the coveted zero backlash for the X and Y axis. Darn that leaves the Z (up and down), the problem being that there is no easy way to use two apposing ball screws for the Z.
Time to compromise since the Z rarely gets used for precise circles and such instead mostly you plunge down thus only going in one direction and drastically lessening the consequences of not having absolute “0” backlash. For the Z I I went with the high end rolled ball with a “preloaded” ball nut, that single preloaded nut cost more than the two nuts for the other axis but aging it’s forking out more money since on preloaded nut cost more than two standard ball nuts but in this case it’s again worth it even though not a zero backlash arrangement it’s still much better than a single standard ball nut.
Additionally the quality and setup of the mounting hardware is another consideration. Yea I planed on, well hang-down-blocking is the only appropriate term that comes to mind, my precision ball screws by supporting the X & Y on only one side with a single low cost low quality ball bearing instead of on both ends with precision mounting hardware.
Setting up the Taig mill, funny they don’t really come “turn-key” there is still quite a bit of work and learning involved before you’re machining anything, I soon discovered that not all controller electronics are equal. Shouldn’t have been a surprise, after all an Xmod CB is not truly proportional, and the old Iwaver CB although an improvement is in no way equal to the Mini-Z CB, which in turn is not a KoPorpo AD Band Mini-Z CB, and like building a race car to compete at the track a bigger motor is not always a good choice nor is that AD band board necessary. After the type of ball screw mod the motor choice was the second major change to the now lamented blissful ignorance of my throw a lipo in an Xmod and its as “good” as a Mini-Z CNC retrofit learning level. After slogging through books, videos, and browsing CNC forums and the like I started to notice quite a few qualifies in statements about stepper motors, like you can do “almost” as much with a steeper, or “nearly” anything you “might” want to do, those red flags led me to a disturbing discovery almost all of the what I term “Pro” CNC retrofit gurus after starting with stepper motors in their projects later upgraded to servo motors for their own personal home mills, there goes the budget again. BTW just like RC forums CNC forums have good, lopsided, and bad advice, it’s a matter off sorting out the members into their actual skill, experience, and even honesty levels then relating what they have to say to what you want to do always taking anything anyone says with a healthy grain of salt.
Long story but true small desktop mill size servo motors are hard to come by, most end up being high torque DC motors with an encoder thrown on, which although fast and again suitable for larger less precise work can have cogging problems, and for high resolution work I needed a motor made to be a servo motor with a good optical 500 CPR encoder otherwise there would be no point in moving up form a stepper motor.
Ok by this time that $45large price tang on the Haas was starting to look like a deal, not really it turns out that the old “you get what you pay for” saying needs to be balanced with “only if you know what you need” and a few other qualifies. Turns out that yes after selling off most of the parts I originally ordered for my X2 CNC mill retrofit, the new parts did not cost all that much more, although admittedly there is a lot more work involved not only in tracking them down but also in the installation.
After the modified CNC mill is 100% complete I will list each individual part and it’s source, but until I have concrete proof that each part is doing the job I wanted it to I don’t want to recommend any specific parts or choices.
These are the major changes I made to my original X2 mod plans:
1. Not just ball screws but “high precision” ball screws with zero or near zero backlash ball nuts. Along with “precision” ball bearing mounting hardware.
2. Actual servo motors with high quality encoders. Usually recommended for faster return speeds but in this case they are for high resolution accuracy.
3. Reliable servo drivers for glitch free operation, I’m going with individual Gecko G-320’s instead of a ready-built 4-axis all in one controller/ps/driver unit.
4. 54v 15amp power supply, with additional regulated 12 and 5 vdc outputs, for encoders, relays, and other controller hardware.
5. Planned addition of a Gecko G-100 “G-Rex” USB/Ethernet controller module, not cheep at $400 and requires updated controller software, most PC controller programs like Mach-3 are still working on compatible versions so I decided to wait until all of the bugs have been worked out before taking the plunge, but in the end a good controller module will be a must have.
6. An enclosed flood coolant system that not only lubricates and cools the piece while cutting, but washes away the debris cleaning a clean path for the cutting tool to aid in extreme cutting accuracy on extra small “micro-sized” parts as well as a clean cut finished surface without excessive polishing.
7. Vibration dampening, again for precision and finish.
8. Little bells and whistles that are often overlooked but can make all the difference in the world, like; limit switched, computer controlled spindle speed, computer controlled operation of extras like the coolant system, so you don’t have to be present 100% of the time during slow cutting processes.
9. At this time a high quality tool changer is not in the budget but a tool change high switch and program macro will make the whole tool change process much less labor intensive.
What prompted me to make most of the above changes to my original X2 modification plans was visiting some new buds (yea their machinists which apparently causes them to drink Budweiser I hope it’s not catching) and seeing a couple of retrofitted X2 mills in operation, they where great but all except one similar to what I’m describing above where not suitable to the type of work I want to do.
while I work on getting one that will hopefully do what I really want.
Santa Please: Haas OM-1A
Office Mill; 8" x 8" x 12" (xyz), 5 HP, 30,000 rpm ISO 20 taper spindle with 20 tool carousel, includes Visual Quick Code, 1MB, Beacon Light, coolant pump, high-speed machining, etc.
At a buck under $45K it’s sadly just a little out of my price range so it’s time to mod something
The challenge is to make a home desktop mill that will let you do the same type of precision micro work without robbing a bank first. Enter the Xmod mill otherwise known as the Seig X2 Mini-mill sold by Harbor Freight, Grizzly, and others.
At around $500 the Seig has a great price tag but as far as precision marching goes its pure slop, and even worse it’s manual. However as a solid piece of iron for the foundation of a DIY CNC retrofit project it’s darn near perfect.
I actually started my CNC adventure last year but soon discovered that like modifying micro/mini RC cars sometimes what you order is exactly what you get but not always what you really needed.
Definition: Backlash - play or lost motion between loosely fitting machine parts.
That’s the real enemy, a Seig X2 mill can have up to 0.1” of backlash in the X & Y and I don’t’ even want to think about the Z axis slop. The little Taig CNC desktop mill, approx. $2.3K as a turn key CNC mill, I’m currently using has around 0.02” which although an improvement is far from the ideal since a critical eye can detect discrepancies down to 0.001” and even that can be too much for perfect fitting micro car parts. So basically I want a mill with effectively “0” measurable backlash.
The backlash fix starts with ball screws but like modding our cars success depends on choosing the right parts and how you install them. I needed/wanted that zero backlash ideal but it turns out that most of the ball screw Seig X2 turn key packages and kits although nice and a great price are in what I call the Xmod class, great for making small display panels, 2 to 3 inch parts, and other home CNC projects where a high degree of precision isn’t exactly necessary but not something that will let you compete on the tack with a Mini-Z in other words not precise enough for the micro mini car parts I wanted to make. Most use inexpensive rolled ball screws with lead errors of up to .004 inches per foot along with single ball nuts so that they can still have as much as .02” of backlash making them no more precise than a Taig or Sherline at best.
The simple solution would be precision machine ground zero backlash ball screws with high quality zero backlash ball nuts, but again the price!!! Parts like those are why that Haas costs $45K. Never fear there is usually always a solution you just need to know what it is and why you need it, simple really go for high end rolled ball screws that have a minimum of 0.001” of lead accuracy some are now available at affordable prices that actually exceed the quality of low end machined ball screws, then use two apposing ball nuts so that you can tighten them against each other sandwiching the ball screw threads between them and eliminating the backlash. Takes more room and requires modification of the mill frame itself, along with doubling the cost which is why it’s not popular as a turn key kit or package but in the end can achieve the coveted zero backlash for the X and Y axis. Darn that leaves the Z (up and down), the problem being that there is no easy way to use two apposing ball screws for the Z.
Time to compromise since the Z rarely gets used for precise circles and such instead mostly you plunge down thus only going in one direction and drastically lessening the consequences of not having absolute “0” backlash. For the Z I I went with the high end rolled ball with a “preloaded” ball nut, that single preloaded nut cost more than the two nuts for the other axis but aging it’s forking out more money since on preloaded nut cost more than two standard ball nuts but in this case it’s again worth it even though not a zero backlash arrangement it’s still much better than a single standard ball nut.
Additionally the quality and setup of the mounting hardware is another consideration. Yea I planed on, well hang-down-blocking is the only appropriate term that comes to mind, my precision ball screws by supporting the X & Y on only one side with a single low cost low quality ball bearing instead of on both ends with precision mounting hardware.
Setting up the Taig mill, funny they don’t really come “turn-key” there is still quite a bit of work and learning involved before you’re machining anything, I soon discovered that not all controller electronics are equal. Shouldn’t have been a surprise, after all an Xmod CB is not truly proportional, and the old Iwaver CB although an improvement is in no way equal to the Mini-Z CB, which in turn is not a KoPorpo AD Band Mini-Z CB, and like building a race car to compete at the track a bigger motor is not always a good choice nor is that AD band board necessary. After the type of ball screw mod the motor choice was the second major change to the now lamented blissful ignorance of my throw a lipo in an Xmod and its as “good” as a Mini-Z CNC retrofit learning level. After slogging through books, videos, and browsing CNC forums and the like I started to notice quite a few qualifies in statements about stepper motors, like you can do “almost” as much with a steeper, or “nearly” anything you “might” want to do, those red flags led me to a disturbing discovery almost all of the what I term “Pro” CNC retrofit gurus after starting with stepper motors in their projects later upgraded to servo motors for their own personal home mills, there goes the budget again. BTW just like RC forums CNC forums have good, lopsided, and bad advice, it’s a matter off sorting out the members into their actual skill, experience, and even honesty levels then relating what they have to say to what you want to do always taking anything anyone says with a healthy grain of salt.
Long story but true small desktop mill size servo motors are hard to come by, most end up being high torque DC motors with an encoder thrown on, which although fast and again suitable for larger less precise work can have cogging problems, and for high resolution work I needed a motor made to be a servo motor with a good optical 500 CPR encoder otherwise there would be no point in moving up form a stepper motor.
Ok by this time that $45large price tang on the Haas was starting to look like a deal, not really it turns out that the old “you get what you pay for” saying needs to be balanced with “only if you know what you need” and a few other qualifies. Turns out that yes after selling off most of the parts I originally ordered for my X2 CNC mill retrofit, the new parts did not cost all that much more, although admittedly there is a lot more work involved not only in tracking them down but also in the installation.
After the modified CNC mill is 100% complete I will list each individual part and it’s source, but until I have concrete proof that each part is doing the job I wanted it to I don’t want to recommend any specific parts or choices.
These are the major changes I made to my original X2 mod plans:
1. Not just ball screws but “high precision” ball screws with zero or near zero backlash ball nuts. Along with “precision” ball bearing mounting hardware.
2. Actual servo motors with high quality encoders. Usually recommended for faster return speeds but in this case they are for high resolution accuracy.
3. Reliable servo drivers for glitch free operation, I’m going with individual Gecko G-320’s instead of a ready-built 4-axis all in one controller/ps/driver unit.
4. 54v 15amp power supply, with additional regulated 12 and 5 vdc outputs, for encoders, relays, and other controller hardware.
5. Planned addition of a Gecko G-100 “G-Rex” USB/Ethernet controller module, not cheep at $400 and requires updated controller software, most PC controller programs like Mach-3 are still working on compatible versions so I decided to wait until all of the bugs have been worked out before taking the plunge, but in the end a good controller module will be a must have.
6. An enclosed flood coolant system that not only lubricates and cools the piece while cutting, but washes away the debris cleaning a clean path for the cutting tool to aid in extreme cutting accuracy on extra small “micro-sized” parts as well as a clean cut finished surface without excessive polishing.
7. Vibration dampening, again for precision and finish.
8. Little bells and whistles that are often overlooked but can make all the difference in the world, like; limit switched, computer controlled spindle speed, computer controlled operation of extras like the coolant system, so you don’t have to be present 100% of the time during slow cutting processes.
9. At this time a high quality tool changer is not in the budget but a tool change high switch and program macro will make the whole tool change process much less labor intensive.
What prompted me to make most of the above changes to my original X2 modification plans was visiting some new buds (yea their machinists which apparently causes them to drink Budweiser I hope it’s not catching) and seeing a couple of retrofitted X2 mills in operation, they where great but all except one similar to what I’m describing above where not suitable to the type of work I want to do.
Favorite quote; “dude. it's a peice of wire.....” by ph2t.
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color0
- bitPlaya'
- Posts: 161
- Joined: Mon Nov 28, 2005 7:30 pm
- Location: Silicon Valley, CA
- Contact:
Thanks for all the info LBRC. Where'd you get your ball screws from and what selection did the shop/company have?
I feel like a noob all over again, totally in the dark (despite the hours and hours of homework... I suspect you had the same experience) regarding the good, the bad, and the good-for-the-money stuff and starting out with only the very very basics.
.02" = .5mm, if it's just the ball screws that is some terrible backlash. So we use the same ball screw, but two ball nuts and preload them against each other? It sounds straightforward enough on paper.
I should be getting the exact same Taig mill as yours (2019ER), so perhaps we have a common platform to test out things. Mine is coming from the eBay dealer with a StepmasterNC controller and stepper motors and I'm using Mach3 and MadCAM with it (good and cheap, total $354 for both just because I'm still a student).
Good luck with yours, knock on wood for mine...
I feel like a noob all over again, totally in the dark (despite the hours and hours of homework... I suspect you had the same experience) regarding the good, the bad, and the good-for-the-money stuff and starting out with only the very very basics.
.02" = .5mm, if it's just the ball screws that is some terrible backlash. So we use the same ball screw, but two ball nuts and preload them against each other? It sounds straightforward enough on paper.
I should be getting the exact same Taig mill as yours (2019ER), so perhaps we have a common platform to test out things. Mine is coming from the eBay dealer with a StepmasterNC controller and stepper motors and I'm using Mach3 and MadCAM with it (good and cheap, total $354 for both just because I'm still a student).
Good luck with yours, knock on wood for mine...
Greyscale Racing
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LBRC
- bitGangsta'
- Posts: 361
- Joined: Sun May 02, 2004 1:25 am
- Location: North West
- Contact:
When it comes to upgrading to ball screws the Taig closely resembles an Epoch being a terrific little mini mill for the price but it wasn’t desighned to be upgraded. I know it’s possible to add ball screws to a Taig mill because I did find one or two projects mentioning them out of thousands of other retrofits for larger mills but I never could find any plans, or even detailed photos. It’s quite a bit smaller than an X2 weighing only 60 lbs compared to the Seig X2’s 140 lbs and although the table movement is similar it will require a smaller diameter and higher pitch ball screw, the ball screws and nuts I’m using in the X2 won’t work for the Taig.
One other thing to note about a Taig or Shearline is that being basically hobby mills they have smaller spindles that are not compatible with the larger more common industry standard collets and other similar hardware.
I’ve been using the Mach 3 controller software, it seems to be a pretty good choice, primarily due to the support and shear number of other users, as far as CAD/CAM software even though I have/have access to what are definitely better programs for the design side I ended up using BabCad for the CAM side of the house, maybe when I’m more fluent in G-code basics I’ll switch back but that may be awhile.
One other thing to note about a Taig or Shearline is that being basically hobby mills they have smaller spindles that are not compatible with the larger more common industry standard collets and other similar hardware.
I’ve been using the Mach 3 controller software, it seems to be a pretty good choice, primarily due to the support and shear number of other users, as far as CAD/CAM software even though I have/have access to what are definitely better programs for the design side I ended up using BabCad for the CAM side of the house, maybe when I’m more fluent in G-code basics I’ll switch back but that may be awhile.
Favorite quote; “dude. it's a peice of wire.....” by ph2t.
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color0
- bitPlaya'
- Posts: 161
- Joined: Mon Nov 28, 2005 7:30 pm
- Location: Silicon Valley, CA
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So the first thing I have to do when I get the mill is to take it apart... lol. Looking at the exploded views for the Taig mill, adding ballscrews isn't especially difficult, just expensive and tedious. I'm being naive here, but perhaps good leadscrews with plenty of graphite lubricant is also an option.LBRC wrote:When it comes to upgrading to ball screws the Taig closely resembles an Epoch being a terrific little mini mill for the price but it wasn’t desighned to be upgraded. I know it’s possible to add ball screws to a Taig mill because I did find one or two projects mentioning them out of thousands of other retrofits for larger mills but I never could find any plans, or even detailed photos. It’s quite a bit smaller than an X2 weighing only 60 lbs compared to the Seig X2’s 140 lbs and although the table movement is similar it will require a smaller diameter and higher pitch ball screw, the ball screws and nuts I’m using in the X2 won’t work for the Taig.
For example, http://www.universal-thread.com/lead.htm advertises a best of 0.0003 in/ft, while some of the 'precision' ground ball screws were 0.0005in/ft. I still don't know what to believe yet.
I don't think that will be a huge problem... so long as endmills fit and are secure and precise enough. Empty hope, given the backlash you just mentioned?One other thing to note about a Taig or Shearline is that being basically hobby mills they have smaller spindles that are not compatible with the larger more common industry standard collets and other similar hardware.
I chose MadCAM because 1) it works within Rhino, and 2) it's easier for me to use over BobCAD/CAM. Maybe I'm dumb, but it took me some time in that software to get the toolpaths going on a simple servo mount, and then I couldn't figure out how to rotate the rotary axis to allow me to finish up the other side. Maybe it's a demo version thing.I’ve been using the Mach 3 controller software, it seems to be a pretty good choice, primarily due to the support and shear number of other users, as far as CAD/CAM software even though I have/have access to what are definitely better programs for the design side I ended up using BabCad for the CAM side of the house, maybe when I’m more fluent in G-code basics I’ll switch back but that may be awhile.
Greyscale Racing
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LBRC
- bitGangsta'
- Posts: 361
- Joined: Sun May 02, 2004 1:25 am
- Location: North West
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It’s replacing the low profile compact side-post lead-screw nuts with ball-nuts that has me worried.
The ball-nuts are by necessity much thicker and thread into a mounting block from one end. Which may make it a very tight squeeze, and will likely require a little pocket machining of the table base, saddle casting, and spindle housing just to make room for the larger ball-nuts and mounting blocks. One solution might be to use smaller ball-screws with very small ball-nuts. But either way it still ends up being complicated which is basically why I decided to work on the X2 first even though the Taig is already CNC, eventually I will try to add ball screws to the Taig, “tedious” about sums it up. Unless I end up trading it off for a small desktop 4 axis horizontal mill/lathe for making wheels, I keep running across then loosing a link to a pretty cool setup that didn’t look too hard to make.
As long as you keep the lead-screws clean the Taig mill should do just about anything you need for your car and or prototyping. What it is not doing for me is small smooth thin walled arc in arc or circle in circle type cuts, for example if you where trying to recreate the inside of an Epoch wheel every time the X & Y change directions you get that backlash error so one wall of the circle ends up being noticeably thinner than the other and if your not careful the small .05” end mill you wound need to use can/will snap as the cut gets deeper.
Let me know how MadCam works out for you as I said BobCad was more of a desperation move for its CAM program with advanced features like 3D pocketing to get things running, it was also an extreme good deal for me being an extra/unused licensed copy from a friends shop they use 4 copies and I chipped in for the 5th in a package deal. The primary reason they like and use BobCad is for ease of use in 2D for laser and plasma torch cutting operations, basically it lets them sketch it and cut it, or more to the point with BobArt and BobNest they scan it, nest it, then cut it all very quickly. My brother uses Ailbre Pro which comes with MecSofts Visual Mill 3 (w/RhinoCam) but to get advanced features like 3D pocketing and such I’d need to fork out a good deal of extra cash for RhinoCam Pro at around $4K for it alone or Visual Mill 5 which includes it. Gets a bit expensive doesn’t it?
The ball-nuts are by necessity much thicker and thread into a mounting block from one end. Which may make it a very tight squeeze, and will likely require a little pocket machining of the table base, saddle casting, and spindle housing just to make room for the larger ball-nuts and mounting blocks. One solution might be to use smaller ball-screws with very small ball-nuts. But either way it still ends up being complicated which is basically why I decided to work on the X2 first even though the Taig is already CNC, eventually I will try to add ball screws to the Taig, “tedious” about sums it up. Unless I end up trading it off for a small desktop 4 axis horizontal mill/lathe for making wheels, I keep running across then loosing a link to a pretty cool setup that didn’t look too hard to make.
As long as you keep the lead-screws clean the Taig mill should do just about anything you need for your car and or prototyping. What it is not doing for me is small smooth thin walled arc in arc or circle in circle type cuts, for example if you where trying to recreate the inside of an Epoch wheel every time the X & Y change directions you get that backlash error so one wall of the circle ends up being noticeably thinner than the other and if your not careful the small .05” end mill you wound need to use can/will snap as the cut gets deeper.
Let me know how MadCam works out for you as I said BobCad was more of a desperation move for its CAM program with advanced features like 3D pocketing to get things running, it was also an extreme good deal for me being an extra/unused licensed copy from a friends shop they use 4 copies and I chipped in for the 5th in a package deal. The primary reason they like and use BobCad is for ease of use in 2D for laser and plasma torch cutting operations, basically it lets them sketch it and cut it, or more to the point with BobArt and BobNest they scan it, nest it, then cut it all very quickly. My brother uses Ailbre Pro which comes with MecSofts Visual Mill 3 (w/RhinoCam) but to get advanced features like 3D pocketing and such I’d need to fork out a good deal of extra cash for RhinoCam Pro at around $4K for it alone or Visual Mill 5 which includes it. Gets a bit expensive doesn’t it?
Favorite quote; “dude. it's a peice of wire.....” by ph2t.
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color0
- bitPlaya'
- Posts: 161
- Joined: Mon Nov 28, 2005 7:30 pm
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I'll take your word for it, and if I can get some high quality replacement leadscrews, will do so ASAP. At this point in time, it seems that leadscrews are cheaper to get to good tolerances than ballscrews, so more than likely I will be heading for that route. Luckily for me my design is mostly straight lines, so if something goes that 0.05mm out of whack it's usually not a big deal. However, I do have some radiuses and holes so I'll just have to wait and see how the little Taig handles them.LBRC wrote:As long as you keep the lead-screws clean the Taig mill should do just about anything you need for your car and or prototyping.
I've been told not to go so deep, especially since I'm using even smaller endmills than you are (1mm... that's like a needle
). The rule I kept on finding on CNCzone was that you never go deeper than your endmill is wide, so my step depth for now is limited to 1mm (of course I can buy bigger endmills later on, and probably will, but this is the test run/prototyping/very small production run, and I couldn't justify all the hardware at first).Will do with MadCAM. However, unless you're still under "student" status, it's not that affordable.
Greyscale Racing
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LBRC
- bitGangsta'
- Posts: 361
- Joined: Sun May 02, 2004 1:25 am
- Location: North West
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CNC word of the month: “Fixturing”
Meaning the system and or device used to hold the piece you want to work on firmly in place. This amazing word is the key when searching the net for all those nifty little devices used to hold the part you want to make in place.
For example you want to make front knuckles for your micro/mini project car that will have too ball bearings, one on each side, and two posts top and bottom, a delicate little 3D part with problems, the bearing holes must be perfectly aligned on one axis but you have to go at them from two different sides, meanwhile the posts must also be aligned on another axis and again you have to go at them from two different sides, what you going to use to hold them and line them up perfectly as you flip them around, and more importantly how are you going to repeat the process over and over so each piece is exactly the same.
Example of what you can find with “fixturing”: http://www.workholding.com/miteeprod.htm
Used in a sentence: Fixturing can get expensive.
Coolness part award winners, remember it’s good to want:
Taig: http://www.youtube.com/watch?v=w0-tXDEv ... ted&search
X2: http://littlemachineshop.com/video/ToolChangeDemo.mpg
http://littlemachineshop.com/products/p ... &category=
Meaning the system and or device used to hold the piece you want to work on firmly in place. This amazing word is the key when searching the net for all those nifty little devices used to hold the part you want to make in place.
For example you want to make front knuckles for your micro/mini project car that will have too ball bearings, one on each side, and two posts top and bottom, a delicate little 3D part with problems, the bearing holes must be perfectly aligned on one axis but you have to go at them from two different sides, meanwhile the posts must also be aligned on another axis and again you have to go at them from two different sides, what you going to use to hold them and line them up perfectly as you flip them around, and more importantly how are you going to repeat the process over and over so each piece is exactly the same.
Example of what you can find with “fixturing”: http://www.workholding.com/miteeprod.htm
Used in a sentence: Fixturing can get expensive.
Coolness part award winners, remember it’s good to want:
Taig: http://www.youtube.com/watch?v=w0-tXDEv ... ted&search
X2: http://littlemachineshop.com/video/ToolChangeDemo.mpg
http://littlemachineshop.com/products/p ... &category=
Favorite quote; “dude. it's a peice of wire.....” by ph2t.
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color0
- bitPlaya'
- Posts: 161
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Hah. 
I'll be sure to use that one a lot. (The Taig vise I found in the package works quite well for fixturing.)
I'm still missing the controllers and rotary table, but they're supposed to be here tomorrow and I'm getting impatient. Who'd a thunk that I could have paid in June and not receive the stuff until the summer vacation was up!
I'll be sure to use that one a lot. (The Taig vise I found in the package works quite well for fixturing.)I'm still missing the controllers and rotary table, but they're supposed to be here tomorrow and I'm getting impatient. Who'd a thunk that I could have paid in June and not receive the stuff until the summer vacation was up!
Greyscale Racing
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Nasphere
- bitNinja
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man, where is codesuidae????
i sent him a lot of i think 7 steppers with 200 steps/rev along with a 500 step/rev optical encoder and various other things... Just by those specs, are those any good? my neighbor gets a few of these from time to time. they were used in machines that placed the little gold wire between the A & K of LEDs. So the machine is probably accurate to the .001" or better.
I'm curious if he's done anything with em yet... He moved and had to sell his mill sadly, but i'm sure he'll get back into it.
i sent him a lot of i think 7 steppers with 200 steps/rev along with a 500 step/rev optical encoder and various other things... Just by those specs, are those any good? my neighbor gets a few of these from time to time. they were used in machines that placed the little gold wire between the A & K of LEDs. So the machine is probably accurate to the .001" or better.
I'm curious if he's done anything with em yet... He moved and had to sell his mill sadly, but i'm sure he'll get back into it.
Whack!
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LBRC
- bitGangsta'
- Posts: 361
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200 steps per revolution is good but 60 oz/in is not strong enough to be useful on a mill that cuts anything other than plastic or wax. For comparison the stepper motors on the small Taig mill are 270 oz/in steppers and I’m using 350 oz/in servo motors on the X2. The voltage is also lower than used for most cnc machining applications for comparison I’m running the Taig at 48v and the X2 at 54volts. Because of the low voltage they might be useful on some sort of robotics project.
I am using 500 CPR optical encoders on the X2’s servo motors, but any usefulness for an optical encoder depends on it’s compatibility with the motor and driver you want to use it with, in other words it needs to fit the motor and have the correct output for the driver. For example the Gecko G320 drivers I’m using on the X2 require a digital quadrature TTL encoder output. BTW a 500 CPR quadrature output gives you 2,000 increments per revolution which can indeed be quite accurate, for example with the 0.2 pitch ball screws I’m using with the X2 that works out to be 0.0001 inches of movement per increment. And of course stepper motors of course don’t need encoders.
Color
Did it all show up?
I am using 500 CPR optical encoders on the X2’s servo motors, but any usefulness for an optical encoder depends on it’s compatibility with the motor and driver you want to use it with, in other words it needs to fit the motor and have the correct output for the driver. For example the Gecko G320 drivers I’m using on the X2 require a digital quadrature TTL encoder output. BTW a 500 CPR quadrature output gives you 2,000 increments per revolution which can indeed be quite accurate, for example with the 0.2 pitch ball screws I’m using with the X2 that works out to be 0.0001 inches of movement per increment. And of course stepper motors of course don’t need encoders.
Color
Did it all show up?
Favorite quote; “dude. it's a peice of wire.....” by ph2t.
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color0
- bitPlaya'
- Posts: 161
- Joined: Mon Nov 28, 2005 7:30 pm
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Yeah it has (effin' finally!). I've got 3 of the axes running fine at the moment, the rotary's arriving tomorrow (says UPS).
I ran a couple practice programs through the mill, I couldn't see much backlash. I guess I should measure this with a dial indicator vs. Mach 3, right? And then Mach 3 has a built-in feature to compensate for backlash, which I hope it works. The concept is pretty spiffy. Feel free to dump all your CNC know-how on me now, I will probably need it tomorrow onwards.
Thanks LBRC!
I ran a couple practice programs through the mill, I couldn't see much backlash. I guess I should measure this with a dial indicator vs. Mach 3, right? And then Mach 3 has a built-in feature to compensate for backlash, which I hope it works. The concept is pretty spiffy. Feel free to dump all your CNC know-how on me now, I will probably need it tomorrow onwards.
Thanks LBRC!Greyscale Racing
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LBRC
- bitGangsta'
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For straight cuts Mach-3 can do a pretty good job when it comes to eliminating backlash, but for arcs (i.e. circles and such) it has limitations.
This photo is a good example it’s a 1-3/8” diameter hole cut with the Taig and a 4mm endmill using three outward spiral pocket cuts with backlash compensation so that the mill approached the final circle wall at a low angle and already in motion, for now ignore the three horizontal cut lines they are caused by head alignment and I’m told that much can be done about them with work tramming (making the head absolutely perpendicular to the table) and tightening up the dovetails as the slides get worn in, look instead at the vertical lines and you can clearly see the entry marks (left indent or flat spot) and transition marks (right) as the screws made the change from a + direction movement to a – movement even with the backlash compensation, there are identical marks for all four +/- transitions (0° +Y to -Y, 90° +X to -X, 180° –Y to +Y, & 270° –X to +X), since backlash compensation programs stop and rewind the target axis to compensate for the backlash they also have to stop all other movement momentarily at the transition while doing so which is what still causes the transition marks. Depending on your monitor if you look very closely you may also be able to see the chatter/increment marks which are also partially caused by backlash that no program can reduce, and with multiple mirrored complex arcs (squiggly line cuts) like for a Micro-T chassis nose piece even with the compensation the top and bottom are still not “absolutely” identical since one side is cut from right-to-left and the other from left-to-right but more importantly accompanying screw or axle holes often come out different even with the compensation so that you have to go back and compensate for them in the CAD drawing if you want them to look perfect, lol but then the drawing looks off and you have to remember what you've done to compensate.
Progress on the X2 has been slow but I’m very close to the testing stage, needed to cut out part of the mill base and reorder a longer ball screw for full movement on the Y axis since I’m using two ball-nuts, and since the darn base was too big to put on the Taig I had to file and grind out all that steel by hand, which unfortunately looks like crap but was worth it not only to save the inch of travel that would have been lost by adding the additional ball-nut but because I managed to gain an additional 0.25” in the process, partial compensation for the blisters
. Also because I’m using larger screws and therefore larger ball-nuts than the typical X2 retrofit I needed to cut out some of the table bottom and slide block for the X axis too but fortunately I could do most of that on the Taig.
Hope to have it up and running by the weekend, am anxious to compare finish cut quality and micro part size detail to see if all the effort and expense was worth the trouble.
BTW about Tramming
(insuring the mill head and column are absolutely perpendicular to the table)
Even with a good indicator it’s bloody hard to perfectly tram the head on the Taig or X2, from my point of view the whole idea of having a tilting Z axis is 99% worthless especially when working on micro sized parts where 1/100 of a degree of can make noticeable differences. At first I thought “hey great” but it turns out to be one of those forehead smacking “that’s right stupid-head since it’s the table that moves there’s a big difference between tilting the table and the object on the table.” This nifty little tool http://www.cartertools.com/nanotram.html
looks like it could be a big help but since I will never (cross my fingers) tilt the head on either mill again the price seems a bit steep for a two time use (once for each mill) especially when for the X2 for absolute perfection I will most likely simply use the mill itself to resurface and level/tram the steel table top, unfortunately that would make a mess of the Taig’s finished aluminum surface.
.
This photo is a good example it’s a 1-3/8” diameter hole cut with the Taig and a 4mm endmill using three outward spiral pocket cuts with backlash compensation so that the mill approached the final circle wall at a low angle and already in motion, for now ignore the three horizontal cut lines they are caused by head alignment and I’m told that much can be done about them with work tramming (making the head absolutely perpendicular to the table) and tightening up the dovetails as the slides get worn in, look instead at the vertical lines and you can clearly see the entry marks (left indent or flat spot) and transition marks (right) as the screws made the change from a + direction movement to a – movement even with the backlash compensation, there are identical marks for all four +/- transitions (0° +Y to -Y, 90° +X to -X, 180° –Y to +Y, & 270° –X to +X), since backlash compensation programs stop and rewind the target axis to compensate for the backlash they also have to stop all other movement momentarily at the transition while doing so which is what still causes the transition marks. Depending on your monitor if you look very closely you may also be able to see the chatter/increment marks which are also partially caused by backlash that no program can reduce, and with multiple mirrored complex arcs (squiggly line cuts) like for a Micro-T chassis nose piece even with the compensation the top and bottom are still not “absolutely” identical since one side is cut from right-to-left and the other from left-to-right but more importantly accompanying screw or axle holes often come out different even with the compensation so that you have to go back and compensate for them in the CAD drawing if you want them to look perfect, lol but then the drawing looks off and you have to remember what you've done to compensate.
Progress on the X2 has been slow but I’m very close to the testing stage, needed to cut out part of the mill base and reorder a longer ball screw for full movement on the Y axis since I’m using two ball-nuts, and since the darn base was too big to put on the Taig I had to file and grind out all that steel by hand, which unfortunately looks like crap but was worth it not only to save the inch of travel that would have been lost by adding the additional ball-nut but because I managed to gain an additional 0.25” in the process, partial compensation for the blisters
. Also because I’m using larger screws and therefore larger ball-nuts than the typical X2 retrofit I needed to cut out some of the table bottom and slide block for the X axis too but fortunately I could do most of that on the Taig.Hope to have it up and running by the weekend, am anxious to compare finish cut quality and micro part size detail to see if all the effort and expense was worth the trouble.
BTW about Tramming
(insuring the mill head and column are absolutely perpendicular to the table)
Even with a good indicator it’s bloody hard to perfectly tram the head on the Taig or X2, from my point of view the whole idea of having a tilting Z axis is 99% worthless especially when working on micro sized parts where 1/100 of a degree of can make noticeable differences. At first I thought “hey great” but it turns out to be one of those forehead smacking “that’s right stupid-head since it’s the table that moves there’s a big difference between tilting the table and the object on the table.” This nifty little tool http://www.cartertools.com/nanotram.html
looks like it could be a big help but since I will never (cross my fingers) tilt the head on either mill again the price seems a bit steep for a two time use (once for each mill) especially when for the X2 for absolute perfection I will most likely simply use the mill itself to resurface and level/tram the steel table top, unfortunately that would make a mess of the Taig’s finished aluminum surface.
Actually I was sort of hoping that you’d get up and going enough to surpass my meager entry level knowledge and discover the many annoying little details, solutions, answers and whatnot that I “um” could usecolor0 wrote:...Feel free to dump all your CNC know-how on me now, I will probably need it tomorrow onwards.
.Favorite quote; “dude. it's a peice of wire.....” by ph2t.
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color0
- bitPlaya'
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Thanks for the heads-up on Mach 3 and tramming, LBRC. That little alu disk costs quite a lot. I'm sticking to a dial indicator though because I can't think of an easy way to square the rotary table using that eztram thing.
How much backlash does your Taig have again? I can only turn the axes dials a couple degrees either way before the table starts moving. I've also considered the idea of a preloaded leadscrew; I think it would work, just don't know how much graphite I'd have to stick in there to keep it from binding up.
[vent]And the 1mm endmills I bought, advertised as 6.3mm cutting length, turned out to be 1mm for the first 2.5mm, and then back up to 3mm. Wtf mate.[/vent]
How much backlash does your Taig have again? I can only turn the axes dials a couple degrees either way before the table starts moving. I've also considered the idea of a preloaded leadscrew; I think it would work, just don't know how much graphite I'd have to stick in there to keep it from binding up.
[vent]And the 1mm endmills I bought, advertised as 6.3mm cutting length, turned out to be 1mm for the first 2.5mm, and then back up to 3mm. Wtf mate.[/vent]
Greyscale Racing
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LBRC
- bitGangsta'
- Posts: 361
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So far the best I’ve managed for the Taig is around 0.006” of measured table only backlash but that changes a bit when you are putting a load on the screws when cutting, to me what ends up being important is the amount of actual deviation on the finished part. Much seems to depend on how your cutting the part and what material it is, for example on the aluminum Micro-T nose piece I seem to be getting the best results entering 0.018” for my compensation value on the Y axis, it mostly seems to be a mater of trial and error.
Endmill selection and ordering is a pain in the ass. I hate having nowhere local to shop and “see” what the tool actually looks like, website descriptions and photos are seldom dependable. Spendy little suckers too, I’ve stopped ordering mills and bits from places like McMaster-Car and MSC Direct unless I absolutely can’t find what I want elsewhere, too expensive with less than accurate/reliable descriptions, the endmills and bits I’ve been getting from sites like Use-enco.com and WTTool.com have been just as good if not better quality wise at much more affordable prices.
BTW speaking of breaking endmills, limit switches and a panic button are a must do modification, takes too long to fiddle with the mouse for an emergency stop. Oh yea and perfect belt alignment on the Taig is nothing short of vital, when the belt slips off you loose an endmill, or the belt breaks and it’s $7.65 for the belt and a new endmill, yep broke my first belt this week took out a nice little Garr 4mm three flute carbide endmill before I could kill the power.
For me today’s WTF goes to good old UPS, was expecting my Tormach Tooling System order to arrive today but when I got home no parts, odd. Fired up the computer, clicked on the Quantum View tracking link and my package arrived at the local UPS hub about 20 miles down the road a 2:45 AM which in my experience is right on schedule but it’s status is listed as “Exception” and WTF??? under description it states “ADVERSE WEATHER CONDITIONS CAUSED THIS DELAY” so it arrived at the local hub but couldn’t be delivered because it’s quite possibly the nicest day we’ve had this summer, 75 degrees with sunny clear blue skies and just enough of a light breeze over the water for sailing. Unusual maybe but I’d hardly call it “adverse” what too nice and they had to take the day off for a picnic, or too much sun caused daydreaming driver without sunglasses to wreck? Wouldn’t be so bad but today being Friday I now won’t get the parts until Monday and I had hoped to have the X2 up and running this weekend.
Endmill selection and ordering is a pain in the ass. I hate having nowhere local to shop and “see” what the tool actually looks like, website descriptions and photos are seldom dependable. Spendy little suckers too, I’ve stopped ordering mills and bits from places like McMaster-Car and MSC Direct unless I absolutely can’t find what I want elsewhere, too expensive with less than accurate/reliable descriptions, the endmills and bits I’ve been getting from sites like Use-enco.com and WTTool.com have been just as good if not better quality wise at much more affordable prices.
BTW speaking of breaking endmills, limit switches and a panic button are a must do modification, takes too long to fiddle with the mouse for an emergency stop. Oh yea and perfect belt alignment on the Taig is nothing short of vital, when the belt slips off you loose an endmill, or the belt breaks and it’s $7.65 for the belt and a new endmill, yep broke my first belt this week took out a nice little Garr 4mm three flute carbide endmill before I could kill the power.
For me today’s WTF goes to good old UPS, was expecting my Tormach Tooling System order to arrive today but when I got home no parts, odd. Fired up the computer, clicked on the Quantum View tracking link and my package arrived at the local UPS hub about 20 miles down the road a 2:45 AM which in my experience is right on schedule but it’s status is listed as “Exception” and WTF??? under description it states “ADVERSE WEATHER CONDITIONS CAUSED THIS DELAY” so it arrived at the local hub but couldn’t be delivered because it’s quite possibly the nicest day we’ve had this summer, 75 degrees with sunny clear blue skies and just enough of a light breeze over the water for sailing. Unusual maybe but I’d hardly call it “adverse” what too nice and they had to take the day off for a picnic, or too much sun caused daydreaming driver without sunglasses to wreck? Wouldn’t be so bad but today being Friday I now won’t get the parts until Monday and I had hoped to have the X2 up and running this weekend.
Favorite quote; “dude. it's a peice of wire.....” by ph2t.
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color0
- bitPlaya'
- Posts: 161
- Joined: Mon Nov 28, 2005 7:30 pm
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I agree with you on endmill selection, so I bought a few 4-flute 3mm endmills, 3mm shank so that they can't possibly get it wrong, lol... they'll also come in handy for some of the larger parts that the 1mm endmills would probably just break on.
How do you determine the best belt tension? Right now I have it on "tight", but with about 5mm of movement if I press down on the belt at the midway point.
The computer has a big ESC button I use as a panic button. I've had to use it twice already, dear gods...
I can probably get MadCAM to program in a little backlash compensation, I'll explore the thing some more these last two days before school.
Bought a cute little vise from Enco, it's supposed to be good. It IS very small, 2.6" long, haha, and fits very neatly on the 4" rotary table. I wonder if their endmills are better/cheaper than the $5.70 ones I got off USA Carbide.
How do you determine the best belt tension? Right now I have it on "tight", but with about 5mm of movement if I press down on the belt at the midway point.
The computer has a big ESC button I use as a panic button. I've had to use it twice already, dear gods...
I can probably get MadCAM to program in a little backlash compensation, I'll explore the thing some more these last two days before school.
Bought a cute little vise from Enco, it's supposed to be good. It IS very small, 2.6" long, haha, and fits very neatly on the 4" rotary table. I wonder if their endmills are better/cheaper than the $5.70 ones I got off USA Carbide.
Greyscale Racing