Author Topic: 3d printer - Leapfrog creatr conversion  (Read 5614 times)

Offline BillTodd

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3d printer - Leapfrog creatr conversion
« on: October 25, 2021, 11:19:55 AM »
Finally remembered to take some pictures ...

I'm converting an old Leapfrog Creatr 3d printer to a Core XY design (core xy  is an arrangement of belts that allow the motors to be mounted on the frame)

The creatr is a stout design from a few years ago. The rod linear rails used are unfortunately rather wobbly and the leapfrog dual extruders are rather crude so replacing them with cheap hywin clones seemed the best option . 

I'm using a Bigtreetech Octopus board , with tmc2209 drivers, and their 3.5 inch touch screen.

The Saturn resin printer has found a good use printing various part. 

It's still a work in progress , and I have still to decide exactly what to do with the hot-end/extruder , other than I want it to be easily removable and swapable with other work heads (hence what you see in the pictures are just place holders for the yet-to-be-designed parts).
« Last Edit: August 08, 2022, 03:38:16 PM by BillTodd »
Bill

Offline Brass_Machine

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Re: 3d printer - Leapfrog creatr conversion
« Reply #1 on: October 26, 2021, 11:00:13 AM »
Hey Bill

That's cool! I did not know Leapfrog even made a 3D printer. I like the core XY design... I hopefully I will be on my way to building one soon as well.

Eric
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Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #2 on: October 28, 2021, 04:13:48 PM »
Having fun with some extreme belt resonance ATM.

Not sure if I should add tension or let it off   - seems OK at slow speeds but much above G0 F15000 starts it honking like a mule  and then it quietens down at 20000 again (both way too fast to print but rapid moves are at this speed)

More tuning required
Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #3 on: October 30, 2021, 02:16:02 PM »
I really did not think this would work as an MLSA part, so just  printed the one half of the aluminium parts as is.

So what we have here, is a geared extruder  (5:1) using a tiny 35mm stepper from a 8" disk-drive . I have replace one end cap with a 3d printed part (with the intension of replacing both end caps). It'll have a couple of bond-tech type grippers and a sprung lever to pinch the filament

The large gear (80T) is printed while the small gear , 16T, is a nylon(?) part from some random printer scrap . I have a 3d printed 16T gear with works but is a tight fit .

It required a little hand finishing to fit the stator exactly centred (the print was a little tight) and the bearing fits always require a slight clean-up.




Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #4 on: November 01, 2021, 11:18:08 AM »
Tadpole 2

Aligning two plastic stepper motor halves is somewhat more challenging , but with a little kinetic adjustment , it does work.

Now I have to finish the rest of the printer to try it out
Bill

Offline PekkaNF

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Re: 3d printer - Leapfrog creatr conversion
« Reply #5 on: November 02, 2021, 01:19:22 AM »

...but with a little kinetic adjustment , it does work.

Care to explain? Something like percussive maintenance comes into my mind, but probably not....

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #6 on: November 02, 2021, 07:26:13 AM »
Similar process , one fixes something that once worked but now doesn't  the other get something to work that never did.

tap, tap twist ... tap tap  twist , HAMMER HAMMER oops  that sort of things :-)
Bill

Offline PekkaNF

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Re: 3d printer - Leapfrog creatr conversion
« Reply #7 on: November 03, 2021, 06:28:19 AM »
Thank you. All clear now. I have done my share of tap-tap-tapiti-tap and tweak-tweak-blimey adjustments myself....sometimes even in system that mechanical stickiness, analog measurement (and sometimes even control loop) and digital/SW controls....sometimes it is hard to know even where to start.

Hope this gets sorted with relative ease.

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #8 on: November 05, 2021, 12:10:38 PM »
Finally got around to wiring and  the extruder mount.

The connector is a 41612/3 but I didn't have one in stock (and Farnell wanted 18 quid for one or 250 for a 100) so had to make one from two bits of a full size 96way one .

There's wiring for dual extruders, 3 fans and a few spares for whatever comes up

Bill

Online awemawson

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Re: 3d printer - Leapfrog creatr conversion
« Reply #9 on: November 05, 2021, 12:41:55 PM »
Neat  :thumbup:
Andrew Mawson
East Sussex

Offline WeldingRod

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Re: 3d printer - Leapfrog creatr conversion
« Reply #10 on: November 06, 2021, 11:42:28 AM »
That is some proper ship-shape wire tendering!  It's going to pay off in reliability!

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Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #11 on: November 06, 2021, 04:44:33 PM »
Thanks :-)

I'm interested in how the resin printed parts will hold up over time.  It is surprising how the material changes : It comes out of the vat quite soft and sticky. After a half-hour or so exposed to a few watts of violet/blue light (405nm not really Ultraviolet) it hardens and dries. It can be filed , sanded, drilled, tapped easily.

After a few days , in normal light , it is noticeably harder and , in the case of white resin, changes colour from a ivory to a brilliant white (the hard resin is very fluorescent so I suspect the colour is the result of the final stages of polymerisation ). It also becomes noticeably more brittle, less flexible.



Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #12 on: November 06, 2021, 04:55:08 PM »
I've got the extruder mounted and wired. Heater block and fan are working , but the motor is not being driven (it's wired ok so must be a config issue).

I managed to squirt some filament by hand 

My Z axis home switch mount and cam prints failed  ( almost certainly) because of the low temperature as the resin gets very viscous below about 20'C. I'll have to revisit my cupboard heater tomorrow to get them printed.

 
Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #13 on: November 07, 2021, 11:17:37 AM »
Fixed the extruder motor problem : it seems that by default the forth motor is used as a second Z axis , so a simple matter of shifting the driver and plugs along to the next slot .

The Tadpole extruder seems to work well  motor runs cool at 300mA .

Just got to sort the Z axis home switch
Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #14 on: November 08, 2021, 05:08:39 PM »
well, we have a print ... of sorts

I'm beginning to think the Tadpole may have been an extruder too far...

It seems to work fine then randomly miss steps as if something was jamming inside.  I kept upping the motor current to compensate until it overheated and seized (plastic warping in the heat)

Print quality is OK though (without cooling fan ATM)

Not sure what to do now: make the tadpole out of aluminium as unoriginally intended or try to find the source of the random jams.
Bill

Offline MetalMagus

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Re: 3d printer - Leapfrog creatr conversion
« Reply #15 on: November 11, 2021, 07:08:39 AM »
Noticed you said you had used resin parts. On the Voron printer forum they advise against resin parts, especially if the print chamber is going to be heated. The reason given was that the resin parts are prone to "creep" over time so you begin to see fit and tolerance issues.

Just something to bear in mind if you start having any issues that are not easily identified.

Sean

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #16 on: November 11, 2021, 10:42:10 AM »
Yes thanks Sean,

The extruder is very much an experiment, it was intended to be made in aluminium.

I've had experience with resin parts and heat , they do odd things  like cracking apart at modest temperatures , while at the same time being almost immune to the soldering iron!

I might investigate some higher temperature resins.

In the meantime, I have rebuilt the extruder with a number of fixes which should hopefully  stop it jamming .

« Last Edit: November 11, 2021, 11:20:55 AM by BillTodd »
Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #17 on: November 12, 2021, 05:29:36 PM »
Well I finally have a finish print

Lots of modifications to the tadpole prototype : Better spacing for the gears (it was a little too tight) ,Captive nut instead of threading into the plastic  and machining the bearing and stator fit to reduce the amount of 'fitting' required  etc. etc.

While I was at it I increased the side of the extruder gear bearing so I can get it out without disassembling the motor .

Still no part cooling.

Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #18 on: November 13, 2021, 03:33:18 PM »
This is what I like about resin printing...

This fan duct would be nearly impossible to make in one piece with any other method.

 
Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #19 on: November 19, 2021, 04:43:43 PM »
Quick update.

Printer is working. This is its forth print in progress.

The extruder is working well when it works but is still being unreliable at times.


The resonance is fixed (for now) by switching off the tmc stelthchop mode, which is a pity because it's not as quiet now. I've tried to get Marlin's hybrid mode to work but it doesn't seem to want to disable stelthchop ever ???? (Expert advice welcome)

Speed is still being limited by acceleration, again marlin advice welcome!



Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #20 on: January 23, 2022, 07:50:08 AM »
I was not happy with the glass bed , I could not get things to stick to it and it took an age to heat to even 50'C, its 240w heat way too small for such a large piece of glass.

While watching the Prusa XL launch , I was taken by the idea of a segmented bed , so decided to build one for the FrogSpawn. While sourcing a suitable piece of cast tooling plate from the 'works' my friend overheard what I wanted it for and promptly donated ten 120x100 heater pads  - :-) perfect.

The mod involves bending the front of the existing Z plate , to remove a nice little 'finger-shear'  between the plate and the front of the frame. and mounting it below the ball-screw nuts to increase Z range. Four rectangular bars fixed to the underside of the Z-plate and a rear support , stiffen the Z-plate and provide mounting points for the Kastal 300 bed-plates

The heated bed-plates will mount on springs at each corner , with screws for adjustment.  Once properly adjusted the bed should stay trammed and level.

The nine 240vac 120w heaters will be controlled from a RaspberryPi Pico with a 9 way PID written in microPython  . 

The problem I have yet to solve is how to control the bed temperature from Marlin or, via g-code, from the BTT display controller.

Ideally, Marlin would be able to talk to the Pico via a spare serial port and report temperatures back to the display. However, I found no way to do this in Marlin :-(

My work around plan , is to intercept or monitor the serial data between the BTT LCD and the BTT Octopus board and intercept the appropriate M-codes .

Interception , means breaking the like between the two boards and inserting the Pico , but now the Pico would have to handle all the traffic and could be a potential bottleneck. 

Monitoring means just sniffing the data going to the Octopus board and picking up the bed control M-codes as they pass by. In order to let Marlin know the bed temperature , the centre plate's thermistor would have to be paralleled with both the Pico and the Octopus  . Any thoughts?
Bill

Offline WeldingRod

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Re: 3d printer - Leapfrog creatr conversion
« Reply #21 on: January 23, 2022, 08:49:45 PM »
3 point mounts are your friend on this stuff...  much easier to adjust.

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Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #22 on: January 24, 2022, 06:28:47 AM »
Yes, I did look at 3point mounts, but decided that corner mounts were simpler to implement . Hopefully, itll be just the one PITA adjustment session.
Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #23 on: March 01, 2022, 08:42:57 AM »
Progress is slow here ATM  -I'm  lacking motivation and easily distracted

Such as converting a microwave oven to a UV curing device for the resin printer.

And now, the oven's transformer is pulling me towards making a small spot-welder .

And Stefan Gotteswinter's new grinder has me thinking about a surface grinder project

 :proj:
Anyway back to the segmented bed  - which I'm calling the Lillipad ( just to maintain the aquatic theme :-))

I've got the bed plates mounted and, as predicted above, levelling is a PITA but do-able.

I've bonded the nine heater pads to the plates and (since the photo) connected earth leads an thermistors to each.

All I have to do is complete the software to control it  - ( zero motivation )

Wire it  - (majorly conflicted as to where to put the controller   -i.e. put the SSRs on the Z plate to  reduce the number of wires  or drop a multicore cable down to a nice, and easily constructed, box on the base plate ?  - I'm almost certainly over thinking it.




Bill

Offline BillTodd

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Re: 3d printer - Leapfrog creatr conversion
« Reply #24 on: March 01, 2022, 08:56:17 AM »
Microwave oven curing station:

The cube in the centre is the yellow  PLA one printed above  - it fluoresces intensely in the 405nm blue light   
Bill