Thanks. Here is a video of a Corian part I cut yesterday. This is an end support for a chip guard roller.
https://youtu.be/snQbzr1wJ1g
Thanks. Here is a video of a Corian part I cut yesterday. This is an end support for a chip guard roller.
https://youtu.be/snQbzr1wJ1g
I really like that tapping guide idea. This is a great thread for newbies to read as it shows many approaches to getting the job done that don’t show up many of the other threads.
This past weekend I made a bit more progress on the build. I machined 6 Corian parts to support the chip guard rollers. I was inspired by Wade O Design to use a similar chip guard roller setup. I could not however find any rollup blinds that I liked so I decided to make my own spring retract rollers. I didn't take any photos of this but they are just a piece of PVC pipe, two end caps, a 3/8 inch shaft, and a spring that I made out of music wire.
I am using captive nuts in slots in the front rectangular piece of Corian to hold the parts together.
The Corian pieces clamp to the granite surface plate with two set screws per side. I have drilled at least 44 holes in the granite up to this point and I do not plan on drilling any more.
The vinyl I bought turned out to be too sticky I think. I am worried that chips will stick to it and get wound up in the roller and end up on the wrong side of the sheet. I think I will switch to polyethylene sheeting as it should be hard for anything to stick to it.
Here is another update.
I designed this PCB to add three relays and fix a problem with the cheap Chinese RNR motion control board I am using. The RNR board works fine but I had linearity problems with the analog voltage output. The RNR board alone gave up to about a 30% speed error. The PCB I designed buffers the output of the RNR board to reduce the spindle speed error to about 0.5%.
Here it is installed.
Next I cut a large rectangle out of the wood base the machine sits on so I can access the internal space. I mounted the electronics inside.
Here is the inside. You can see the VFD is outputting 301.45 Hz. Mach 3 requested 18000 rpm which is 300 Hz.
I also assembled this metal junction box to house all the 240V wiring. It has two fuses, a power switch, and a switched outlet for the spindle water cooling pump. I machined a polyethylene bushing to feed the wires through and into the wood machine stand.
Here it is with the lid on. The air solenoid for the mist system is mounted to the side of this box.
Next I worked on cable and hose management. My idea was to use a piece of 1/2 inch PEX pipe to support all the wires and hoses that go to the moving spindle. The PEX slides over an aluminum pin on each end that allows it to rotate but not slide up or down.
Here is the support arm for the other end of the PEX on the back of the gantry.
Continued in the next post...
Here you can see the PEX tube installed with the hoses and cable attached to it. I also installed the e stop switch which is sitting on the granite machine base.
Here is a close up of all the connections. You can also see the aluminum clamp that I made to hold the mist system to the Z axis plate.
Finally, I started on adding limit switches. So far I have only installed the Y axis switches.
I still need to finish adding limit switches and work on making some side walls to control the chips. As of right now the chips fly out several feet from the machine and make a mess on the floor.
Thanks for posting up your build ,really enjoyed seeing the excellent pictures of its construction.Looks to be a great balance of size power and precision.Congratulations.
What kind of hoses are you using for the water-cooled spindle?
Nice build. It makes so much sense to use a granite surface plate as the base for diy cnc machines. They are relatively inexpensive. They arrive flatter and squarer than any diy machine bed ever could. Granite is super strong, stiffer and harder than steel and has significantly better vibration damping than steel, aluminum or even cast iron. Datron uses granite beds and their machines are awesome.
A little tip, if you ever find an issue with the stability of the threaded inserts held in place with epoxy, I recommend using extra long bolts to go through to the other side of the granite. I.e. Drill all the way through the surface plate and attach the gantry or rails with 8" bolts going into a steel plate on the other side (of the surface plate). This clamping method provides a much stronger grip which will prevent rails being ripped out from a deep up-cut.
I used a mix of clamping with long bolts and threaded inserts to attach actuators to my epoxy granite base. I know from experience that, over time, the bond between epoxy and another hard material (like granite or steel) can be broken relatively easily with a strong knock or pull. Using wrench-tightened long bolts help minimize that risk.