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Bubblegum CNC - Proxxon MF70 CNC Conversion Kit

by goopyplastic, published

Bubblegum CNC - Proxxon MF70 CNC Conversion Kit by goopyplastic Nov 5, 2012

Description

Information at https://www.youtube.com/playlist?list=PLYxf6JVpXtyO_PyjGGxkbttEl6JiWM5uO

NOTE: The lower axis is offset .7mm I am not sure if this is specific to my mill or not. If you find that it doesn't fit well let me know and I will upload a neutral version (or if you need a specific offset).

Recent Comments

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I have modified it to accept NEMA 23 motors. There are step by step guides (plenty of images) in my blog (http://www.elektroquark.com) in Spanish showing how I am configuring my MF 70 with your awesome kit (work in progress).
I will use printed flexible couplers too.
Thank you very much for this kit.
For those who have asked. For those who will ask. I believe this is correct. I watched the video many times to try to extract the BOM since it was never fully gone over in any of the videos :P Goopy! If you see this would you mind chiming in as to whether this looks right? Hope this helps.

-Z Axis

-Printed Parts -
m70-zlimit
m70zplate-626-bearing-lower
m70zplate-626-bearing-upper
m70zplate-626-plate
m70zplate-626-stepper

-Hardware-

-Bracket Assembly
10x #4 3/4" Self Tapping Counter Sunk Screws
4x #4 1/2" Self Tapping Counter Sunk Screws

-Stepper Motor Assembly
4x M3 x 10mm Coarse Thread Socket Cap Screws
4x M3 Washers
2x 626-2RS Bearings(or regular)
1x 4x5x25mm Shaft Coupler(4mm side drilled out to 4.5mm)
1x Dubro #40 Brass Locking Collar (3/16" Drilled 4.5mm)

-Assembly To Mill
4x M3 20mm Coarse Thread Socket Cap Screws

---------------------------------------------------------------

-Lower Axis

-Printed Parts -
mf70lowerplate-626-internal
mf70lowerplate-626-internal-mirror
mf70lowerplate-626-plate
mf70lowerplate-626-plate-mirror
mf70lowerplate-626-stepper
m70-spacer

-Hardware-
-Bracket Assembly
10x #4 3/4" Self Tapping Counter Sunk Screws
4x #4 1/2" Self Tapping Counter Sunk Screws

-Stepper Motor Assembly
4x M3 x 10mm Coarse Thread Socket Cap Screws
4x M3 Washers
2x 626-2RS Bearings(or regular)
1x 4x5x25mm Shaft Coupler(4mm side drilled out to 4.5mm)
1x Dubro #40 Brass Locking Collar (3/16" Drilled 4.5mm)

-Assembly To Mill
4x M3 20mm(flexible on length) Self Tapping Button Head

---------------------------------------------------------------

-Upper Axis

-Printed Parts -
mf70upperplate-626-internal
mf70upperplate-626-plate
mf70upperplate-626-plate-unblocked-mirror
mf70upperplate-626-stepper
m70-spacer

-Hardware-
-Bracket Assembly
10x #4 3/4" Self Tapping Counter Sunk Screws
4x #4 1/2" Self Tapping Counter Sunk Screws

-Stepper Motor Assembly
4x M3 x 10mm Coarse Thread Socket Cap Screws
4x M3 Washers
2x 626-2RS Bearings(or regular)
1x 4x5x25mm Shaft Coupler(4mm side drilled out to 4.5mm)
1x Dubro #40 Brass Locking Collar (3/16" Drilled 4.5mm)

-Assembly To Mill
4x M3 20mm(flexible on length) Self Tapping Button Head

---------------------------------------------------------------

-Total Quantites Of Hardware

30x #4 3/4" Self Tapping Counter Sunk Screws
12x #4 1/2" Self Tapping Counter Sunk Screws
8x M3 20mm(flexible on length) Self Tapping Button Head
6 x 626-2RS Bearings
3x 4x5x25mm Shaft Couplers (Drilled out to 4.5mm)
3x Dubro #40 Brass Locking Collars 3/16" (Drilled out to 4.5mm)
12x M3 x 10mm Coarse Thread Socket Cap Screws(or similar)
12x M3 Washers
6x Omron micro Switch D2F-01FL(or any pin/plunger micro switch)

---------------------------------------------------------------

Alternative Ideas-- The shaft couplers could be substituted with something like this thingiverse.com/thing:9622

***Note: You will most likely want some type of glue like gorilla glue and REALLY small self tapping/metal screws for adhering a couple of the plates together, as well as the micro switches to the appropriate places outline in goopyplastic's video.
a) I used ABS, it shouldn't matter ABS vs. PLA as long as the motors don't get hot. b) the main reason is because the stock endplates are not very strong so you can't tighten the leadscrew nuts very much and this leaves backlash in the system, so yes it is to eliminate backlash (via tightening of the leadscrew nuts).

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I have modified it to accept NEMA 23 motors. There are step by step guides (plenty of images) in my blog (http://www.elektroquark.com) in Spanish showing how I am configuring my MF 70 with your awesome kit (work in progress).
I will use printed flexible couplers too.
Thank you very much for this kit.
Dec 12, 2014 - Modified Dec 12, 2014
For those who have asked. For those who will ask. I believe this is correct. I watched the video many times to try to extract the BOM since it was never fully gone over in any of the videos :P Goopy! If you see this would you mind chiming in as to whether this looks right? Hope this helps.

-Z Axis

-Printed Parts -
m70-zlimit
m70zplate-626-bearing-lower
m70zplate-626-bearing-upper
m70zplate-626-plate
m70zplate-626-stepper

-Hardware-

-Bracket Assembly
10x #4 3/4" Self Tapping Counter Sunk Screws
4x #4 1/2" Self Tapping Counter Sunk Screws

-Stepper Motor Assembly
4x M3 x 10mm Coarse Thread Socket Cap Screws
4x M3 Washers
2x 626-2RS Bearings(or regular)
1x 4x5x25mm Shaft Coupler(4mm side drilled out to 4.5mm)
1x Dubro #40 Brass Locking Collar (3/16" Drilled 4.5mm)

-Assembly To Mill
4x M3 20mm Coarse Thread Socket Cap Screws

---------------------------------------------------------------

-Lower Axis

-Printed Parts -
mf70lowerplate-626-internal
mf70lowerplate-626-internal-mirror
mf70lowerplate-626-plate
mf70lowerplate-626-plate-mirror
mf70lowerplate-626-stepper
m70-spacer

-Hardware-
-Bracket Assembly
10x #4 3/4" Self Tapping Counter Sunk Screws
4x #4 1/2" Self Tapping Counter Sunk Screws

-Stepper Motor Assembly
4x M3 x 10mm Coarse Thread Socket Cap Screws
4x M3 Washers
2x 626-2RS Bearings(or regular)
1x 4x5x25mm Shaft Coupler(4mm side drilled out to 4.5mm)
1x Dubro #40 Brass Locking Collar (3/16" Drilled 4.5mm)

-Assembly To Mill
4x M3 20mm(flexible on length) Self Tapping Button Head

---------------------------------------------------------------

-Upper Axis

-Printed Parts -
mf70upperplate-626-internal
mf70upperplate-626-plate
mf70upperplate-626-plate-unblocked-mirror
mf70upperplate-626-stepper
m70-spacer

-Hardware-
-Bracket Assembly
10x #4 3/4" Self Tapping Counter Sunk Screws
4x #4 1/2" Self Tapping Counter Sunk Screws

-Stepper Motor Assembly
4x M3 x 10mm Coarse Thread Socket Cap Screws
4x M3 Washers
2x 626-2RS Bearings(or regular)
1x 4x5x25mm Shaft Coupler(4mm side drilled out to 4.5mm)
1x Dubro #40 Brass Locking Collar (3/16" Drilled 4.5mm)

-Assembly To Mill
4x M3 20mm(flexible on length) Self Tapping Button Head

---------------------------------------------------------------

-Total Quantites Of Hardware

30x #4 3/4" Self Tapping Counter Sunk Screws
12x #4 1/2" Self Tapping Counter Sunk Screws
8x M3 20mm(flexible on length) Self Tapping Button Head
6 x 626-2RS Bearings
3x 4x5x25mm Shaft Couplers (Drilled out to 4.5mm)
3x Dubro #40 Brass Locking Collars 3/16" (Drilled out to 4.5mm)
12x M3 x 10mm Coarse Thread Socket Cap Screws(or similar)
12x M3 Washers
6x Omron micro Switch D2F-01FL(or any pin/plunger micro switch)

---------------------------------------------------------------

Alternative Ideas-- The shaft couplers could be substituted with something like this thingiverse.com/thing:9622

***Note: You will most likely want some type of glue like gorilla glue and REALLY small self tapping/metal screws for adhering a couple of the plates together, as well as the micro switches to the appropriate places outline in goopyplastic's video.
Yet Another Prusa Mendel Z Coupling
by nophead
This comment has been deleted.
Sorry folks, the domain link went bad and I didn't notice. You can find build videos including BOM in the video at my youtube playlist here: youtube.com/playlist?list=PLYxf6JVpXtyO_PyjGGxkbttEl6JiWM5uO
can you please list all hardware.I have some hard time to find the right bearing and screws
thanks
The videos here have the BOM: youtube.com/playlist?list=PLYxf6JVpXtyO_PyjGGxkbttEl6JiWM5uO
Nema 23 would not work with my design as it is.
A very sophisticated design - the proxxon people should hire you... :)

Two questions:
A) What material did you use for the pink prototype - resp. what do you recommend for the whole set? PLA, ABS or?
B) Why did you decide to also redesign the whole assembly that keeps the bearings and spindles in place? Reduced backlash? a defined position for the endstop switches? Or just fun doing it? ;) Some people just add motor holders ...

TIA for your reply!
a) I used ABS, it shouldn't matter ABS vs. PLA as long as the motors don't get hot. b) the main reason is because the stock endplates are not very strong so you can't tighten the leadscrew nuts very much and this leaves backlash in the system, so yes it is to eliminate backlash (via tightening of the leadscrew nuts).
A) I used ABS but at the time that is what I had, PLA should work fine as well.
B) To reduce backlash primarily. The stock plates are not very strong and will deform when the leadscrew nut is tightened. That is a downside of the motor holder conversions although depending on your application the motor holders may work fine.
Thanks. Good analysis of the given construction from your side! Is there any work on FEM analysis of 3Dprinted materials done or under way already? I understand that with the multivariability of the various parameters, this is pretty complex on the first sight. On the second, it could lead to mechanically and morpholically optimized structures - assuming that the material properties are more or less reproducibkle.
Apropos - did you measure the accuracy and repeatable reproduciblity of the milling machine? You also rely on a linear characteristic of the spindles. The thread slope can vary considerably, though. Wikthout demanding too much from the simple design - a servo drive with a linear way transducer like the electromagnetic ones from Tico might be suitable to improve the setup further.
Really like your conversion. I've watched all your videos and am printing out the parts now. Could you provide a BOM for all the other hardware? Thank you.
Hi goopyplastic.

We are currently converting the MF70 at our hackspace to CNC using your kit. Very impressed with it, there's zero backlash on the X and Y axes compared to our old conversion.

hacman.org.uk/cnc-night/ is our current status. As far as we can tell, we have the only bubblegumcnc except yours on the entire internet :)

-Bob
I want to build the second bubblegumcnc, please publish a list of parts please!

Thanks

Daniele
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