I am about to assemble my MPCNC. I am going to be starting out small. 11x12in cutting area.
I am going to be using a 36V motor with a 5mm shaft.
The goal: To be able to cut Acrylic, plastic (HIPS) ,wood and other softer materials. I think the toughest think I plan to cut may be 3mm ACM. I also plan to do some engraving and at some point add a laser for cutting and engraving.
I want to use this to augment my 3D printers. My current project is a flight simulator cockpit, but there is always something I am creating.
So, due to having lots of 3D printers and left over parts, I have a lot of 6mm belts, pulleys, etc. To start, will I be ok to use 6mm instead of the 10mm?
What bits would you use for Acrylic? What about thin plywood?
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There is no harm in using the smaller belt, use matching pulleys. If you start pushing the load on your CNC you can “upgrade” to 10mm belts and pulleys.
The 36 volt motor comment, is this motor to serve as your router? The watts rating will give you a idea if it has the torque to drive your cutting tool
Well, info on the motor is a bit vague. at 24V it spins 4750RPM. However, it is clearly rated at 36V as it is printed on the side of the motor and I pulled it out of a Vacuum that ran on a large 36V battery.
I am going to try it out, but if it does not do what I want, I do have a 25,000RPM 1 HP Craftsman router that will be just fine.
My thought is, if the small motor will do the small jobs, it will be better for me as I will have the router in the same room with me where I work. So, quiet would be nice.
I am going to be using a 36V motor with a 5mm shaft.
The settings for cutting are a balancing act between the diameter of the bit, the number of flutes on the bit, how fast you move the router, and the RPM of the router. For the MPCNC, you will likely want to be in the range of 15K to 20K rpm for most of your work. I don’t know how much torque your motor (with a 4750RPM) will have at 15K.
I do have a 25,000RPM 1 HP Craftsman router
The two problems to be solved by uncommon routers are 1) how to mount them, and 2) how to use 1/8" bits. Being able to use 1/8" bits is very helpful, but most 1 HP and above routers require some sort of add-on to use them. You really want native solution like a collet. Most 1/4" to 1/8" adaptors will cost you some of your Z working distance, plus most have some runout (wobble).
What bits would you use for Acrylic?
You will get notably superior result if you use a bit designed for acrylic. Typically, they have the term “O Flute” in the title. For the MPCNC, I’d look at 1/8” single flute bits of an O flute type.
What about thin plywood?
I like the single flute 1/8” upcut endmill sold by V1. Similar bits are sold on Amazon, though I would recommend, starting out, to purchase one of the name brand bits rather than the cheap ones.
Note that I cut a lot of thin plywood on my machine using a laser module. It works well.