Shapeoko Inspired New Machine Design

discussion of design changes / improvements / suggestions
Post Reply
samc99us
Posts: 270
Joined: Mon Nov 11, 2013 5:20 pm

Shapeoko Inspired New Machine Design

Post by samc99us » Thu Jan 07, 2016 3:59 am

So,

The machine in my signature is running great, but I'm in a never ending quest for more stiffness...until I end up with a HAAS VF9 sitting in my shop haha.

Alas, my budget isn't there, and I enjoy designing routers (mills are another ball of wax). At this point I am going with the largest extrusions that are OpenRail compatible. This means HFS5-4080 on the Y-axis rails (for compatibility with my existing bed which has 4040 y-axis rails, easy enough to swap) and 8020-5010 (50mm x 100mm) on the x-axis gantry. Current plans are a 860mm gantry (giving me 24" of cut area on the x-axis) and sticking with the 1500mm y-axis. I may go a little wider on the gantry, either 930mm or 1000mm, as my current setup supports a 1000mm gantry and I can reduce it in two increments of 70mm. The z-axis is a ballscrew z-axis from CNC4NEWBIE, basically this setup but with a ballscrew (chinese) instead of a ACME threaded rod: http://cnc4newbie.com/store/index.php?r ... duct_id=57

Drive will be my Gecko 540 setup with upgrades to 270 oz-in NEMA23 steppers on all axis, from the 180 oz-in versions I currently have. All plates are 0.25in Aluminum 6061-T651, mostly fixed as I have the material already...I do have 3/8" plate I could use on the x-axis carriage but this required pocket milling for the NEMA23's. 15mm GT3 (ACTUAL Gates powerdrive belts, not chinese knock-offs) will be on each axis with carbon fiber belt clips and a threaded belt tensioning system.

I haven't completed this design but I am looking for some feedback, specifically on the following:
1) X-axis carriage v-wheels. Is 8 per plate overkill?
2) Z-axis, should I run as orientated or flip it and use it as it was intended? The way I have it the router collet would only need to be about 1" below the bottom of the z-axis "carriage", which is really everything but the one plate. This is more Shapeoko 1 esque but follows the CNCRouterParts ballscrew z-axis design. My thought is this is stiffer and you aren't really loosing anything, just need perhaps a little more clearance around tooling?
3) Z-axis. Does anyone have familiarity with this? The price is right and so far the design is checking out. I wish there was one more support bearing for the ballscrew at the top but this isn't really necessary as the bottom of the ballscrew is fully captive between two bearings.
Isometric.JPG
Isometric.JPG (62.33 KiB) Viewed 2478 times
Bottom.JPG
Bottom.JPG (60.25 KiB) Viewed 2478 times
Carriage.JPG
Carriage.JPG (69.58 KiB) Viewed 2478 times
Modified Shapeoko 2: 1500mm fully supported y-axis, 1000 mm 4060 x-axis, ACME Belt Drive Z-axis, Dewalt DNP611, full aluminum t-slot table, 4x NEMA23 180 oz/in stepper motors driven by a G540

bharbour
Posts: 413
Joined: Wed Aug 06, 2014 3:40 pm
Location: Mobile, AL
Contact:

Re: Shapeoko Inspired New Machine Design

Post by bharbour » Thu Jan 07, 2016 4:56 pm

Cool design. I'm thinking about building my own as well, but I'll get away from the delhrin wheels.
No longer have a Shapeoko, but use a machine of my own design...
https://www.youtube.com/watch?v=gFY4gC9TqD0
http://deltaguitarworks.tumblr.com

samc99us
Posts: 270
Joined: Mon Nov 11, 2013 5:20 pm

Re: Shapeoko Inspired New Machine Design

Post by samc99us » Thu Jan 07, 2016 7:27 pm

Well, I have a full design worked up with steel v-rail as well. The only reason I have for moving away from delrin wheels at this point is contamination when milling aluminum, which I simply don't do often enough. I added more wheels for more stiffness, and frankly I think this design is stiffer than 4x steel v-wheels (because your are distributing the load across more bearings and more spacers, which all have some level of flex, its the assembly not just the wheels themselves that matters), and less expensive. The steel vrd1 v-wheels from Inventables come out at $95.60 for this carriage (8 v-wheels in total) whereas the delrin v-wheels come in at $59.96. The steel rail is also significantly more, $18.60 for a 24.5" steel v-rail, $26.15 for stainless v-rail, so $104.6 vs. the openrail at $6/1000mm, or $24.00 for this gantry. In total, the steel v-rail solution is $116.24 more expensive. Can those who have made the switch say the steel solution $116 better? I mean the product I use my router to build starts life as $150 in materials, so in that context it is justifiable. In the $84 vs. $200 gantry question, hmm, not sure.

There is an "easy" way it seems to mount the rail: http://openbuilds.org/threads/strong-ox.914/page-11

Running the numbers above was good exercise. Enough so that I may go with the steel v-rail on the x-axis, since the price delta isn't that bad. one thing to check will be which extrusion I can use.

Since my openrail y-axis is still good, I'll probably go that route still. It stays relatively free of debris.
Modified Shapeoko 2: 1500mm fully supported y-axis, 1000 mm 4060 x-axis, ACME Belt Drive Z-axis, Dewalt DNP611, full aluminum t-slot table, 4x NEMA23 180 oz/in stepper motors driven by a G540

Post Reply