Archive for November, 2008

CNC Engraver Improvements

Previously I’ve written about my CNC build , a sound proof box I made for it and a description of the software I’m using with it.

After some usage I found a few weaknesses in my CNC machine. Today I’m going to cover 3 improvements that target those weaknesses:

  • Installing some new parts from CNCRouterParts (ACME Anti-backlash Nut, Z-Axis Plate and Low Profile Bearing Block)
  • Installing clamp-on couplers from DumpsterCNC
  • Building a custom dust control vacuum system

CNCRouterParts ACME Anti-backlash Nut

Previously I had used these ACME anti-backlash leadnuts from DumpsterCNC. These seem to be a common suggestion on CNCZone. They worked fine except that mounting them onto my 8020 Aluminum frame required some custom mounting brackets. I spent hours designing and making these brackets. I’ve had a few problems with them. One of my brackets was ever so slightly out of alignment causing some binding issues. They also had a few bolts/nuts that could vibrate loose so I had to keep an eye on these and tighten them from time to time. There were no major problems here, but these issues were annoying.

I ordered some ACME Anti-backlash Nuts from CNCRouterParts to replace the ones from DumpsterCNC. I was told these would mount directly onto my 8020 frame without any special brackets. Another advantage is that they are cheaper ($18.50 versus $22.50). As promised they mounted directly to my 8020 frame. I’ve used them for about an hour and they seem to work very well.

In my mind the CNCRouterParts solution is vastly superior to anyone building their frame out of 8020 due to fact that they are way easier to mount. I think that even on most non-8020 machines these would e easier to mount.

CNCRouterParts Z-Axis Plate

As a full discloser, I got this part free of charge from CNCRoutnerParts because I was the first to post an informative blog about other parts I’ve bought from them. I do not feel this has influenced my evaluation of this part.

This plate is well designed and a good deal at $28.75. Originally I spent many hours designing a steel plate solution. This gives more Z axis reach than my steel plate since the router is mounted lower than in my design. The biggest advantage is of this plate is time savings. I could just bolt my K2CNC router mount to this plate instead of spending the time to create my own. If you don’t mind spending a few hours you can save a few bucks by making your own, but I feel its money well spent.

CNCRouterParts Low Profile Bearing Block

As a full discloser, I got this part free of charge from CNCRoutnerParts because I was the first to post an informative blog about other parts I’ve bought from them. I do not feel this has influenced my evaluation of this part.

The low profile bearing block adds about one inch of Z travel to my machine over the standard bearing block because it lets the Z axis plate to travel over it. That said I like the standard bearing block more and after some testing went back to the standard bearing block. One reason is this new block uses a bushing instead of bearings so there is significantly more friction. I found this limited the speed I could run my Z axis at. Another issue is that I don’t need the extra Z travel and the standard block adds a hard stop to my Z axis, which I like as an extra safety precaution. With the low profile block I could run my Z axis rollers off their rails. If you need more Z travel you might want to look at the low profile bearing block, but I’ll stay with the standard bearing block which is an excellent product.

It’s also worth mentioning that the standard blocks are significantly more expensive after adding in the cost of the bearings so if price is a high concern that might give you more incentive to try and use this low profile bearing block.

DumpsterCNC Clam-on Couplers

I wanted to try these couplers from DumpsterCNC instead of the lovejoy connectors I used to mount my ACME screws to my stepper motors. The DumpsterCNC couplers are a little cheaper and they take up less space than the lovejoy connectors. They work just as well as the lovejoy connects so in any future builds I’ll likely use these instead of lovejoy connectors. I have nothing else to say since both products do their job perfectly.

Dust Control Vacuum System

My CNC machine is in an enclosed box so I don’t need to worry about dust getting all over my basement, but I found that having dust get all over my CNC machine was problematic. The biggest two areas of concern were dust on the ACME threads and dust on the roller rails. Instead of trying to stop dust from getting on these parts by covering them I decided to add a vacuum to suck up the dust before it could go on anything.

I bought this vacuum because is small, powerful, and cheap. I fabricated a small mount out of aluminum and wood to attach the vacuum to the router. The only other components I needed were some wire and duct tape. I used the wire as a structure and the duct tape to form a flexible skirt around the router to help suck up the dust. The pictures show this better than I can describe in words.

I am very pleased at how well this works. I really believe this is nearly an optimal solution. It took much less time to build than the solid wood/aluminum skirt designs I’ve seen, and I think this flexible design should perform better. It might not be pretty but it works great!


Here’s a few objects I made while testing.

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