Proxxon MF 70 CNC Conversion with Extended Y axis movement

Well yes, here is another Mf70 CNC conversion :)

I have this machine for nearly ten years, and as all, I've always wanted to convert it to CNC, checking out almost all conversion kits on sale at the pre-3Dprinting times. When I had my 3D printer four years ago, one of the projects that were always in my mind was this conversion.

Throughout the years, I should say that I liked the bubblegum CNC conversion the best, and that was my biggest inspiration for designing my conversion:

https://www.thingiverse.com/thing:33799

However, I wouldn't say I liked the idea of drilling through the original parts, and I always thought that using axial (thrust) bearings instead of roller bearings would be much more appropriate for this machine.

Besides, I've always wanted to imply the Y-axis extension modification, which I first saw it in the following blog:

https://0xfred.wordpress.com/2012/04/17/extending-the-mf70s-y-axis/

It looks like I was not the only one to think these, quite naturally. I've recently realized claustonnesen's excellent conversion, utilizing thrust bearings and extended Y-axis.

https://www.thingiverse.com/thing:4013033

So, based mostly on using thrust bearings principle, and trying to minimize part count, using universal parts for step motor mounting as much as possible, I have designed my conversion parts a year ago and started testing and improving.

Initially, I started with the original axis movement capacities, without the extension, to take one step at a time.

Here is a video from one of my first working conversion:

https://www.youtube.com/watch?v=iyra6zogYK0

Then I worked on the Y-extension:

https://www.instagram.com/p/ByKqxVznUss/

Since then, probably well over a year, I have put the machine on the test, cutting wood, PCB boards and finally milling aluminium. I've realized that by using good quality cutters, milling aluminium, precisely, is a possibility with this machine, which motivated me to finalize my design and publish.

I made some final design iterations on the parts, and here you are.

It worths to note that most people are noticing slight alignment differences on their lead screws, I did too. As you can see in the video showing the initial trials, there was too much wobbling in the X-axis specifically. Later on, I realized that my axis is 0.75 mm offset, which was one of the reasons. On the final iteration, I did some trial and error to align the leadscrew and the hole on my endplates. You may see the work and result in my Instagram post below:

https://www.instagram.com/p/CDYK4dunhXn/

Now my part is perfectly aligned, however, if your application does not perfectly match, please let me know, and I can edit and post new plates that would match.

The X-axis parts are identical, you need to print two of them, and you may attach your stepper motor at any side you like. I like to connect to the left side, as my CNC controlling software moves the table to 0,0 coordinates when the work is finished. If the motor is at the right side, it pulls the table down from there while sitting idle. Having the motor at the left side more or less balances the weight and reduces the load on the slides.

Y and Z axes endplates are single items; you need to print one of each.

I am using Arduino Uno and a CNC shield for running my machine, and I also designed a Z-axis endplate that has an integrated tray for the electronics and a fan mount for an 80mm fan.

Also, I added a tray for the PSU to be attached to the column, with a simple chip guard at the sides to protect the PSU from the chips flying off the machine when milling aluminium.

The motor mounts are universal for NEMA17 motors, so does the spacers. You need to measure the distance of your setup and chose a spacer accordingly. I've added different lengths from 30 to 50mm in 5 mm increments. If you need any different length, please let me know.

In addition to the printed parts, you will need the following hardware to complete the conversion.

o 6mm inner diameter 14mm outer diameter thrust (axial) bearings (minimum 4, preferably 6 pcs.)

o 6 pcs. socket or button head 3mm self-tapping screws (15 to 20mm in length) to mount X and Y endplates.

o 12 pcs. 3mm countersunk self-tapping screws to mount the motor plates and spacers.

o 12pcs. bolts that suit your step motors.

o Couplers of your choice.

Please note that I am currently working on an installation video, and I will publish it as soon as it is ready.

I also have plans to add some more features, a spoiler board to attach wood sheets, maybe end-stop switch holders for the endplates and also some tool holders/hangers to the Z endplate.

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