MakerSlide CNC router

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MakerSlide CNC router

Postby mikegreen » Tue Apr 24, 2012 7:39 pm

cnc-slide.jpg


I have been experimenting with using MakerSlide to create a mixed lead-screw and rack&pinion CNC router. The project is in a very rough state, but folks may want to build on what I have started, or offer improvements, so it seems reasonable to publish initial results. The drawings are in 3D. Bart's 3D drawings are a great help in trying to figure out how things work. Mine are not as good as his, but hopefully helpful in getting across concepts.

If you decide that you want to build part or all of this project, keep in mind that I have no idea of whether or not it will work. So far it seems promising, but this design uses some parts that are expensive enough that I would recommend trying this only if you are fairly tolerant of having parts made several times and are okay if the thing turns out not to work.

The design is done in Autodesk Inventor 2012. This is my first Inventor project, and I'm sure that my inexperience will show when you look at the files. I have tried to assemble the parts so that they move as they do when actually constructed. A zipped version of the Autodesk files may be found here: http://dl.dropbox.com/u/24641716/autocad.zip.

I have also posted the design in STEP format. The STEP files may be found here: http://dl.dropbox.com/u/24641716/cnc-slide.zip.

One of my objectives with this project is to see if I can combine 3D printed parts with MakerSlide. So far, I have been ordering parts from Ponoko. I'm very happy with the speed of delivery and quality of the plastic parts that they have made for me. The current STL files for parts may be found here: http://dl.dropbox.com/u/24641716/STL.zip. If you have any of these parts made using Ponoko or another service, keep in mind that they are just what I presently think will work. I have had to have several of these parts made two or three times. Even with 3D software to help, I find mistakes. I would not recommend that you have these parts produced if you are expecting them to be right the first time.

My current CNC machine is CNCRouterParts based. I used that to produce the aluminum flat parts that I needed for this design. I have included the VCarve Pro files and individual DXF files for those parts in a zip file here: http://dl.dropbox.com/u/24641716/DXF.zip. If you are thinking about building a CNC router, then it's very possible that you don't have one already. As a test, I ordered the same parts that I made from eMachineShop http://www.emachineshop.com/. There is an EMS file that is part of the zip. It cost me around $131 USD to have these parts made. They were produced quickly and are exactly what I expected. If you use the VCarve files, keep in mind that they are in inches while the DXF files are in millimeters. I'm doing this design in millimeters, but my existing machine uses inches. That's why there is a difference.

I have put some photographs of the parts that I have built on Google+. Those, along with some brief notes, may be found here: https://plus.google.com/photos/101440406689536737329/albums/5734777303367817569.

I really like DumpsterCNC parts. You will see those in the drawing for the Z axis. It's a close fit, but it looks like they will work.

It seems that a Bosch Colt router is about the right size for this build. I got my mount from K2 CNC http://k2cnc.com/shop/products.asp?cat=31. The Colt mounts seem to be out of stock at the moment.

For dust collection, my plan is to go with a Kent CNC shoe https://www.kentcnc.net/nc/. I hope this works with the Z assembly. I should find out in a week or so.

My current machine has spindle speed control, which I really like since I cut plastic, MDF, and aluminum. My thought is to use a SuperPID controller http://www.vhipe.com/product-private/SuperPID.htm for the Colt.

The drawings don't show the right stepper motor. I tried the Vextra from Automation Technology (part number in drawing), but that one did not seem right, so I am currently using the KL23H276-30-8A http://www.automationtechnologiesinc.com/products-page/nema-23/nema-23-14-single-shaft-with-flat-282-oz-in with a Gecko G540 that I also got from Automation Technology.

There are quite a few parts from McMaster and Misumi. The rack&pinion, aluminum extrusion, and extrusion connectors are from Misumi. The part numbers are in the drawing. At present, I don't have any plans to put together a bill of materials. There are, for the most part, no screws and nuts shown in the drawings. Sorry about that. If you build some of this, you will probably have to do what I do and have lots of M5 and M4 socket cap screws, lock washers, and flat washers in front of you.

There is a, hopefully minor, annoyance with the drawing. I don't know what I was thinking, but the X and Y axis should be swapped. I am leaving that alone for now as it appears to me that this would be a major re-work of the drawings. When I wire the device, I think that I will swap the X and Y.

I hope all of the URLs work properly. I have not previously used Dropbox or Google+ to share files. I'm happy to upload them here, but a few of the files are big and upload attachment did not seem to like them.

When I get some time, I will post a few of the pictures individually, along with some comments related to what has worked and some problems that I have encountered.

My hope is that I can test some basic cutting in a month or so. I have run out of V Wheels, but have some on order from Inventables. The rest of the aluminum extrusion for the project arrived from Misumi yesterday, so it should not be too long before I can test cutting.
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Re: MakerSlide CNC router

Postby mikegreen » Tue Apr 24, 2012 7:42 pm

P1000410.JPG


Here is a picture of the assembled Z axis that you can also find in the Google+ album. I have not had a chance to test this, but I don't think that there will be any problem. It seems quite sturdy.
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Re: MakerSlide CNC router

Postby mikegreen » Tue Apr 24, 2012 7:45 pm

plastic z spacer with aluminum inserts.jpg


One of the things that I encountered with using plastic is that the eccentric nuts put too much pressure on the plastic and it deformed. I made these aluminum inserts and that helped considerably. In general, I am matching aluminum parts with plastic ones and it seems pretty solid.
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Re: MakerSlide CNC router

Postby mikegreen » Tue Apr 24, 2012 7:51 pm

P1000420.JPG


Here is a picture of the rack and pinion attached to the MakerSlide. I have done some limited testing with this and it seems very sturdy and quite fast. The multiple holes are there because I don't yet know how high to mount the axis that goes across (labeled Y in the drawings and photos). It's not clear to me that the pressure block component is really needed. If it is needed, I need to redesign it because the nut does not turn smoothly. I'm also not sure that you can direct drive a rack and pinion like this. It seems strong, but I see reduction pulleys on other designs. There may be a reason that I will discover when I try to use this to cut something.
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Re: MakerSlide CNC router

Postby sports.racer » Tue Apr 24, 2012 10:40 pm

I like the look of the R&P. Keep us posted.

There's a long thread on CNCZone about using R&P, specifically this item - http://www.cncrouterparts.com/rack-and- ... -p-50.html
You might find some good info there.

I'm about to try cutting some alu with my CNC router, any tips?
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Re: MakerSlide CNC router

Postby mikegreen » Tue Apr 24, 2012 11:48 pm

I'm not very aggressive with my cuts. Cutting out the 0.125" aluminum with a 5/32 end-mill (it's what I had after I broke a couple of 3/32 ones), I ran at 7,500 RPM with a pass depth of 0.003 and a feed-rate of 25 inches per minute. I think the cuts could have been a bit deeper. It took 33 passes to get through the material. Still. I don't at all like the machine vibrating or making weird noises, so I'm very conservative. I would rather that it take longer and not have to worry about it. If you happen to use VCarve Pro, you can see exactly what I did for both the aluminum and plastic cuts by downloading the DXF zip and looking at the VCarve Pro files. In this case I was using a Weldon end mill. Their tool catalog http://www.weldontool.com/catalogs.asp#weldon has a feeds and speeds section that I used as a starting point. I often use Onsrud end mills, particularly for wood and plastic. Their catalogs and tech notes have a wealth of information about cutting different materials. Go to their site http://www.onsrud.com/ and look in the resources section. You will see links to feed and speed and technical articles. I use these all of the time. Inventables has a good selection of Onsrud end mills. Onsrud is a bit more expensive than other end mills, but they make very nice cuts in plastic and wood.
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Re: MakerSlide CNC router

Postby mikegreen » Wed Apr 25, 2012 12:11 am

sports.racer wrote:There's a long thread on CNCZone about using R&P, specifically this item - http://www.cncrouterparts.com/rack-and- ... -p-50.html
You might find some good info there.


Many folks seem to have had very good luck with the R&P system from CNCRouterParts. That's probably what I will use if my idea does not work. I have a CNCRouterParts based machine with lead-screws. It's good stuff. It's definitely faster and more proven to go with the CNCRouterParts R&P system. I'm just curious about whether or not MakerSlide and 3D printed parts can effectively be used in a CNC router design.
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Re: MakerSlide CNC router

Postby sports.racer » Wed Apr 25, 2012 1:18 am

mikegreen wrote:I'm not very aggressive with my cuts. Cutting out the 0.125" aluminum with a 5/32 end-mill (it's what I had after I broke a couple of 3/32 ones), I ran at 7,500 RPM with a pass depth of 0.003 and a feed-rate of 25 inches per minute. I think the cuts could have been a bit deeper.


Thanks for the info. I may give this a go this weekend. Do you think 0.01 would work ok?

Dave
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Re: MakerSlide CNC router

Postby sports.racer » Wed Apr 25, 2012 1:20 am

mikegreen wrote: I have a CNCRouterParts based machine with lead-screws. It's good stuff. It's definitely faster and more proven to go with the CNCRouterParts R&P system. I'm just curious about whether or not MakerSlide and 3D printed parts can effectively be used in a CNC router design.


I have one of those too. Now I'm going to build a laser and this R&P looks intriguing. Wonder about controlling backlash with it.
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Re: MakerSlide CNC router

Postby mikegreen » Wed Apr 25, 2012 2:42 pm

sports.racer wrote:
mikegreen wrote:I'm not very aggressive with my cuts. Cutting out the 0.125" aluminum with a 5/32 end-mill (it's what I had after I broke a couple of 3/32 ones), I ran at 7,500 RPM with a pass depth of 0.003 and a feed-rate of 25 inches per minute. I think the cuts could have been a bit deeper.


Thanks for the info. I may give this a go this weekend. Do you think 0.01 would work ok?

Dave


P1000432.JPG


Here are some Z lift plates that I cut from .125 aluminum. You mentioned that you are building a laser, so these came to mind. These were cut with a 3/32 end mill at 4,000 RPM with a pass depth of 0.005, and a feed-rate of 32 inches per minute. I seem to recall 0.01 working fine on my machine, but there was a bit too much vibration, at least for me, and so I backed off. These three lift plates did not take that long to cut, even with the very shallow pass depth. In the TechShop ShopBot class that I took, my recollection is that the instructor recommended a pass depth of no more than 1/2 the diameter of the mill, as a rule of thumb, if you want good finishes. I'm pretty sure that he was talking about wood. My machine does not have the rigidity to handle deep cuts with aluminum. Even with wood I tend to take shallow cuts so that I get good finishes.

If these lift plates are what you are thinking of making out of aluminum, I would recommend also milling some spacers. This is the second set of these that I made. I put the aluminum plates and the captive nut (McMaster 99051A900) into my vise and ruined the housing around the nut. By making a little spacer that goes around the housing for the nut, you won't damage the nut. It takes a fair amount of force to get the captive nut into the lift plate.
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