Aluminun Extrusion Custom Build

[AZicuRN]

Ok, so after lurking around this site for some time now, I finally decided it was time to actively participate. Not just because I'm itching to start building, but I've seen how others have progressed from the design stage to the build stage. With all the experience and knowledge they got from actively designing their model on the forum, the input they received probably saved quite a few headaches. I've been wanting to design a CNC for quite some time, and I feel like a have a good start, but I would like others' input for how to proceed/criticism/ideas/etc.

Primary goal would be to cut wood, mdf, and hopefully aluminum in slow passes.
The CNC as I have designed it here is made mostly out of T-slots aluminum extrusion 1530, 3/8" VXB sealed v-groove bearings, MDF, and 3/4 angle steel.

This is the X & Y axes. I have not finished the Z carriage yet, but am still working on it. I also did not include the Steppers, ACME rod, or AB nuts yet. Would like to hear what others think before continuing my design.

Thanks.

[AZicuRN]

I know I don't have a completed design here to really give a thorough picture, but I was hoping to get quality input on what I have built so far. I don't have any experience with CNCs, but was really hoping to have a good first build. Any experienced feedback would be greatly appreciated.

Thanks,
Chris

[rowbare]

Have you looked at the http://www.cncrouterparts.com/ offerings? They have some inexpensive linear guides that can be used with 8020 extrusions. They ride on a piece of cold rolled plate. They are certainly less work and possibly less money than the vee rails you are showing. They also have a decent rack and pinion setup. The owner ahren is an active member here.

Depending on your budget, timeline and the want-to-do-it-all-myself factor, you might want to look at a pre-built Z axis. There are several available.

Good luck!

bob

[AZicuRN]

Have you looked at the http://www.cncrouterparts.com/ offerings? They have some inexpensive linear guides that can be used with 8020 extrusions. They ride on a piece of cold rolled plate. They are certainly less work and possibly less money than the vee rails you are showing. They also have a decent rack and pinion setup. The owner ahren is an active member here.

Depending on your budget, timeline and the want-to-do-it-all-myself factor, you might want to look at a pre-built Z axis. There are several available.

Good luck!

bob

Thanks Bob.
I have looked at cncrouterparts.com. I was considering the linear slide/guide that you are talking about when I was first designing the x axis. I decided against them because I figured the rigidity of the system I had designed would hold up better and would wear longer. The steel guide and linear slide on the website appear pretty solid, and that very well may be a better option. I also wanted to try to maintain the same type of components (i.e. bearings) throughout the machine for ease of maintainence/replacement later on down the road.

I agree on the z axis. Of everything I have been reading the do-it-yourself mentality is not all that uncommon. But I have noticed that most people do end up biting the bullet and ordering a z axis; barring that, have trouble with the ones they design themselves. Any suggestions on a prefab z axis? Something easily adaptable to a 1.25 hp porter cable router?

[rowbare]

K2 sells Z axes http://www.k2cnc.com/shop/products.asp?cat=33

gio666 DIY Aluminum cnc router Frame sells them too. He is fairly new and is continually developing new products. He just mentioned that he will soon have a Z-axis using profile rails.

There are others as well, but these two come to mind.

It is probably worthwhile to spend a few bucks on a good Z axis. Because of the size, they are a pain to make and if you have a good one, and you re-design your machine or build a bigger one you can simply re-use it.

bob

[cyclestart]

The z's from gio666 are ball screw driven. I think K2's are acme screw. There are also linear actuators on Ebay, the stuff from 80servo looks interesting.

Gio666 (George of XZeroAutomotion) is smoking busy so prepared for a potentially long wait if going that route. Might depend on size and specification. I'm at 2 months and counting. The quality to price ratio was hard to pass up.

edit/ In fairness to George it should be mentioned mine is a bit of a custom order. He may have 5" ready to ship, you would have to ask.

[Dylwad]

Ill just chime in on the CNCrouterparts slides, I would bet the 1018 CRS plates and carraiges are much stiffer, smoother, and would wear longer than MDF capped with angle iron and V groove bearings. To my surprise, the 1018 CRS is rolled to very tight tolerances, and is very straight. www.onlinemetals.com is the place for it, 5' or less lengths are cheaper to ship, and they give discounts for your first order, and any order over $100

Have you looked at the angle steel thats available? its pretty rough stuff being hot rolled, the cold rolled angle is just a flat strip bent to shape, so it doesnt have the sharp corner needed for the V groove bearings. Most of the DIY routers I see using slides similiar to your design use aluminum angle because its smoother, and has sharp inside and outside corners. The better designs use machined steel plates.

I designed my machine using the carraiges from CNCrouterparts, but bought my own steel plates and cut and drilled them, saved a ton of money. I designed it so there is only .5" of steel protruding from the 8020, and theres a bolt spaced no more than 2 inches apart holding the steel tight to the 8020. My machine is very stiff, cuts aluminum with ease, and has no chatter or racking cutting 3/4" MDF single pass.

I also think having the X axis rails vertical might introduce some flex and racking when the MDF flexes.

The CNCrouterparts carraiges use skateboard bearings, available everywhere for cheap, not that they need replacing really ever as they only see a radial load, and the pre-load is easily adjusted with set screws.

Just thought I would chime in, your design looks great, but seems a pity to have MDF mixed with aluminum extrusion on the important bits.....

with one side of my gantry locked in place, it takes around 50 Lbs of force on the opposite side to rack it .010" this could even be less with a higher pre-load, I set the pre-load so the gantry slides from on end of the table to the other when you lift one side of the machine up less than an inch from level, with no leadscrew attached, of course

Dylan

Thanks Bob.
I have looked at cncrouterparts.com. I was considering the linear slide/guide that you are talking about when I was first designing the x axis. I decided against them because I figured the rigidity of the system I had designed would hold up better and would wear longer. The steel guide and linear slide on the website appear pretty solid, and that very well may be a better option. I also wanted to try to maintain the same type of components (i.e. bearings) throughout the machine for ease of maintainence/replacement later on down the road.

I agree on the z axis. Of everything I have been reading the do-it-yourself mentality is not all that uncommon. But I have noticed that most people do end up biting the bullet and ordering a z axis; barring that, have trouble with the ones they design themselves. Any suggestions on a prefab z axis? Something easily adaptable to a 1.25 hp porter cable router?

[AZicuRN]

Thanks Dylan!

That's just the kind of input I was looking for. I was pretty pleased with my sketchup job of the x axis. I guess I was thinking of the easiest way to make something on my own that would do the job, and you're right, it would be a shame to have the extrusion quality throughout the build, and have the whole gantry riding on MDF. Thanks for pointing that out.

And also, thanks for the pictures of your build. It looks very solid and exactly what I am looking to build.

Are you using the same system on the y axis as well?
Also, curious about your z axis? Is that k2cnc? And did you make your own router mounts for it, or are those prefab too?

Thanks again for the great feedback.

[Dylwad]

The X, Y and Z all use CNCrouterparts carraiges, the router mount is K2 from ebay (worth every penny) and the Z plate and lower bearing block are from CNCrouterparts.com as well.

I found a frued avantu 80 tooth non-ferrous 10" thin kerf blade on amazon for around $30, and used my dewalt miter saw to cut the extrusions, worked great, had to mess with squaring the saw and clamping the pieces down for a while though.

Gecko 251's from http://retromationinc.com/retromation_007.htm
Carraiges, leadnuts, Zplate, Z lower bearing block and motor couplers from www.Finelineautomation.com
8020 from their Ebay garage sale, 5-97" long 1530 pieces needed for the machine, right at 100Lbs.
All steel and aluminum other than 8020 from www.Onlinemetals.com
All hardware from www.boltdepot.com
Angular contact bearings for the acme screws from www.vxb.com I had to make bushings from 15mm to .5" to use A.C bearings on the acme screws.
1/2-10 5 start Acme leadscrews from www.mcmaster.com
Acme thread clamps from www.dumpstercnc.com
Steppers are Keling KL23H2100-35-4B http://www.kelinginc.net/NEMA23Motor.html
Power supply Toroid from http://www.antekinc.com/
Deskcnc for control software

Machine cutting area is 50x25x6.5" Heres a few pics of the finer work its capable of, I'm still in the tuning stage, so theres room for improvement. Ill take a few more pics of the machine too, the 8020/CNCrouterparts carraiges allow some pretty cool ways to mount things, like home and limit switches, wire tracks, gussets, Etc. Amazing what 1/2-10 5 start can do.

Dylan