Micro-Rider : a lightweight "lowrider" needle cutter

I made today the first cuts of my "micro-rider" , widly inspired by the MPCNC and low-rider needle cutter, and moebeast's Foam Ripper.

IMG_20180923_201043.jpg

I tried and do even simpler and less costly with two stepper motors and one servo, a bunch of bearings and a few wheels. Almost all of the rest is On the shelf components.(Video on Youtube).

It adapts to a wide rangle of surfaces, and can go from really small to full sheet of DTFB (but don't have that size this side of the pond).

I may try in a few days to also cut vinyl stickers with it, or later laser ? But in both cases, I'll need to find a better servo since this one has some kind of jitter. (or use a light stepper a la 28BYJ...)
 

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CarolineTyler

Legendary member
Love it, look forward to more details.
I made today the first cuts of my "micro-rider" , widly inspired by the MPCNC and low-rider needle cutter, and moebeast's Foam Ripper.

View attachment 115340

I tried and do even simpler and less costly with two stepper motors and one servo, a bunch of bearings and a few wheels. Almost all of the rest is On the shelf components.(Video on Youtube).

It adapts to a wide rangle of surfaces, and can go from really small to full sheet of DTFB (but don't have that size this side of the pond).

I may try in a few days to also cut vinyl stickers with it, or later laser ? But in both cases, I'll need to find a better servo since this one has some kind of jitter. (or use a light stepper a la 28BYJ...)
Now that is something I want....no, need. I hate the cutting part of making FT planes but don't have the space to permanently allocate to an A1 size cutter and it's baseboard.
 
For now, I'll try to find a better way to control te Z axis, but plan on creating/publishing the parts for it. But since I only have "metric" parts, I'll probably create cleaned up "parametric" plans...
 

dkj4linux

Elite member
For now, I'll try to find a better way to control te Z axis, but plan on creating/publishing the parts for it. But since I only have "metric" parts, I'll probably create cleaned up "parametric" plans...

I've built one of these up and put a laser on it... it works fine for that.

20180915_101909.jpg


It's a bit noisy with all the bb's (mine's running without lube of any kind) but it may be quieter under load and with use and possibly some light lube. It's all 3d-printed and uses the light stepper motor you mentioned... although I did the unipolar to bipolar hack on it to get more torque and connect directly to the RAMPS board. I've been considering it as a compact needle cutter lift mechanism on a reworked carriage for my FoamRipper... possibly integrated into the needle cutter body itself ;)


-- David
 
Yes, I'm considering using one of those steppers too. Only problem I have is with the backlash, but it looks like with the linked slider it would work well... And I'll have to try and unipolarize one too. Thanks for confirming that the stepper works for that purpose :D
 
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(it) uses the light stepper motor you mentioned... although I did the unipolar to bipolar hack on it to get more torque and connect directly to the RAMPS board.
-- David
Hi, Iam considering doing the same mod, but wonder how you manage the much lower Voltage compatibility of the stepper in that case : Does the driver do all the limitking ? Or do you need to do some "magic" to keep it under 5 V (need the full 12V for the other steppers) ?
 

dkj4linux

Elite member
I'm a long way removed from my active engineering days but IIRC it is NOT the "voltage across" them -- but the "current through" them -- that causes a stepper motor to move. At one time, "chopper" drivers were the thing (PWM?) and the driver regulated the current through the coils by "chopping" the much higher voltage across it... i.e. it's a "duty-cycle" thing. I suspect that if you'll check your "other steppers" datasheet you'll find their "rated voltage" is more like 4.2 volts... not 12 volts. At any rate, the little stepper seems quite happy with the same drivers my "other steppers" use... ;)