LinkBack URL
About LinkBacks
You may also want to look at leveling casters. They work well.
http://www.amazon.com/WoodRiver-Machine-Leveling-Caster-Mounted/dp/B0039ZIPL4]Amazon.com: WoodRiver Machine Leveling Caster Plate Mounted 4 Pack: Home Improvement
| | |
vtx1029, I had started looking through that LVL/Steel thread...I'm sure you could park a truck on that frame, but my thinking is to have a more open structure, but I'm sure that would allow more movement.
So I had some time when I got home this evening and started on a concept based totally on LVL construction. The top band is a 9-1/4" LVL, and all the other pieces are assumed to be cut from the same material, 1-3/4" thick. These pieces could also be standard 2x4 material as well; it would make a minor difference in thickness but would limit the amount of LVL material needed.
I threw in some Grizzly G7159 levelers and G8172 casters as placeholders. The distance of the lower band from the bottom end of the legs is determined by the choice of casters and levelers -- the idea is the levelers retract enough to allow the casters to contact the floor only when the machine needs to be moved.
There's a lot of short pieces in the leg assembly, but I guess that's okay. Lag screwing the diagonals in place would require some long counterbored holes to reach through them. Ahren suggested that the CRP4848 base is stiff enough that it doesn't need a table top on whatever structure I made, but maybe a center beam along the long axis would be a good idea.
Anyway, I throw this out as a first cut. Any suggestions?
You may also want to look at leveling casters. They work well.
http://www.amazon.com/WoodRiver-Machine-Leveling-Caster-Mounted/dp/B0039ZIPL4]Amazon.com: WoodRiver Machine Leveling Caster Plate Mounted 4 Pack: Home Improvement
My CRP 48 x 48 build [URL="http://www.cnczone.com/forums/open_source_cnc_machine_designs/144173-crp_4x4.html"] CRP 4x4[/URL]
I had seen those leveling casters but read a thread somewhere that the machine wobbles on the rubber feet of the WoodRiver casters, so I figured it would be better to use a stiffer leveler. The Grizzly I quickly chose may not be the right one, but it seemed like it would work.
I installed the WoodRiver casters on the case for my small router. The rubber feet are stable enough for the small loads I'm subjecting them to. The biggest problem, for me, is that the wheels are very small making it difficult to roll my router over fairly fine debris on my shop floor. I don't think the wheels would work with floor cracks of any significant size.Originally Posted by vbgraves
Bottom line: if you use casters on your machine, get large ones, at least 4".
Last edited by DonFrambach; 05-06-2012 at 02:32 AM. Reason: spelling
So has anyone put a rotary axis on a CRP4848? I was just looking at something like CNC Router Rotational Axis, the 4th Axis, A axis for the engraving machine 1350 | eBayand wondered if it would be straightforward to add something like this, or if it needs to be planned for upfront.
Is there adequate space under the gantry to accommodate something like this? Does a CRP4848 kit offer taller gantries, and if so, how do they affect rigidity when the rotary unit isn't being used? Or have people gained the needed vertical space under the cutting tool by having a removable table section and a drop-in shelf for the rotary unit? I'm just wondering if the support table needs additional features built into it.
Also, assuming a G540 kit, what additional controls hardware would be required besides the motor that would comes with the rotary axis? If a future rotary axis was desired, is a G540 kit still a good choice for expandability? I'm currently thinking of running LinuxCNC, would that make any difference?
Last edited by vbgraves; 05-14-2012 at 09:33 PM. Reason: typo
Its been in the back of my mind. I've seen people put them on the side of the table (extending the gantry on one side) as well as between the first and second extrusion by having part of the spoil board removable.
I think CRP only offer's one size gantry. I think you would be better off planning on making your table bigger and have the rotary built in or placing it along side the X then raising the gantry.
Being the kit uses all the G540's outputs you would either need to lock one of the axis in place and unplug an axis to plug in your 4th axis or get another breakout board and stepper driver to drive it with. I have no idea on the Linux part.
My CRP 48 x 48 build [URL="http://www.cnczone.com/forums/open_source_cnc_machine_designs/144173-crp_4x4.html"] CRP 4x4[/URL]
You might want to consider the CRP NEMA 34 electronics kit. It comes with the PMDX-126 break-out board, which handles up to six axis. Although, I believe, you would have to use a second parallel port.
Another benefit to using the NEMA 34 electronics kit, is that PMDX also sells a motherboard (PMDX-134) and heat sink to mount your G201Xs to. I went with this route to simplify the wiring between the PMDX-126 and the G201Xs down to a 26-pin ribbon cable to the PMDX-134.
I also added a PMDX-107 spindle controller to control my VFD and spindle.
Last edited by Analias; 05-16-2012 at 09:11 PM.
vtx1029, It sounds like mechanically it's not a big deal to implement a removable section of spoil board and drop in a rotary axis as needed.
Analias, if you glance back through this post, you'll see that I had basically talked myself into the NEMA 23 kit, and now you're giving me an excuse to second-guess that choice...thanks alot!
Just something else I'll have to consider. Maybe this first machine won't have a rotary axis, and if I later decide to move up to a NEMA 34 system with a spindle I'll make sure it has some expansion capability.
Thought I'd bring this thread back to life, as I've made some progress towards my goal. I've decided to go with the NEMA34 system since it will allow easier expansion should I decide to add a rotary axis in the future, and I'd rather build my second system first.
I've been working at this from the cheaper side, buying the smaller portions of a complete system so I could get them built and working and hopefully just intall them when I get the mechanical system built. I bought a SuperPID when they went on sale last fall, and I recently completed an enclosure for it and got it working. I'm keeping my eye out for a good deal on a PC 7518 router motor, and will probably buy when the price goes down again on Amazon.
I just ordered the NEMA34 electronics DIY kit from CNCRP and plan on getting that wired up and working before buying a mechanical kit. I figured the mechanical kits would be more likely to undergo design changes/improvements more often than the electronics kits, so procuring in this order might get me a mechanical kit with the most current design. Anyway, I've started spending real money now, so hopefully that will give me the incentive to move along with the project!
Posting Permissions
| | |
