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Cherry Pi III Is Available

Posted by AndyCart 
Re: Cherry Pi III Is Available
July 30, 2016 05:41AM
Do you have the sensor boards in stock Dave, should I just order from escher3d?

Yes, I have them in stock (so does Filastruder for those in the USA).

Delta printer calibration calculator, mini IR Z probe, and colour touch screen control panel: [escher3d.com]

Large delta printer, and other 3D printer blog postings: [miscsolutions.wordpress.com]

Full disclosure: I have a financial interest in sales of the Panel Due, Mini IR height sensor, and Duet WiFi/Duet Ethernet.
Re: Cherry Pi III Is Available
August 01, 2016 06:44AM
Do you have the sensor boards in stock Dave, should I just order from escher3d?

Yes, I have them in stock (so does Filastruder for those in the USA).

Thanks Dave, I put in an order.

I finally got to print a few test pieces and the results were encouraging, especially considering i was using the 3 year old filament that came with my Ormerod. I had a few problems with the extruder, which were fixed by upping the temps 5 deg. More testing and tweaking required though.

I still like the idea of using the metal corners, and while I was unable to find a complete drawing of them, I did find a 3d model on these forums. Overlaying it over the plastic parts, I can see quite a difference...

Assuming it is accurate, the frame would move inwards 3mm, which other than screw up my bed and Smootheboard mounts, I don't think was cause any other issues. I would however need to make the profiles 25mm longer to keep the uprights relative to where they are now.



Pointy's Things
Pointy's Blog
Re: Cherry Pi III Is Available
August 05, 2016 01:34PM
Is anybody interested in buying my cherry pi.It has a e3d v6 lite head and heated bed.It does print but needs calibrating to get it to stick to bed better.
Im in weston super mare.
Re: Cherry Pi III Is Available
August 23, 2016 07:26PM
Is there a clear cut decision on what kind of springs you should buy? Especially for quite long rods? (465mm) Is there any downside with going with stronger springs other than weight?
Re: Cherry Pi III Is Available
October 05, 2016 04:30PM
Was wondering what firmware to run on cherry pi as havent upgraded my for a year or so and wanted to add inductive sensor.
Re: Cherry Pi III Is Available
February 24, 2017 01:12PM
Ping AndyCart,

Is the CAD Source available for the Pi IIIs?

I want to make a custom effector part for my PI, but my modeling program doesn't work well with imported STL files.

Actually, I think all I really need is the center-to-center spacing of the sockets, if that's easier.

Re: Cherry Pi III Is Available
February 27, 2017 02:37PM
I've been working on a Cherry Pi IIIs XL for a while. I built it then put out a few prints after quickly (and badly) calibrating it, then had to shelve the project for a while. I bought a heated bed, boro glass and 30A power supply with the goal of upgrading and making the print surface more stable. I also had a goal of making the wiring better and closing up the base a bit better.

I have an E3D v6 Clone which works fairly well, there are a few variants on this. Most have a throat that have a PTFE insert for some reason. I switched that out for a the all metal one which is how the real E3D is. I also added a Volcano Heat Block and a .6mm Nozzle which suits the type of single wall "spiral vase" prints I plan on making with this. PETG makes fantastic prints like this with larger nozzles. You can still do .2 layer height normal prints that look great as well. I'm using the "Modicum" extruder as it has zero backlash and can handle flexible filaments with ease. I like geared extruders as they have better quality than direct drive. I'm using Maso's effector for the E3D v6 and 8mm balls. The largest 6mm rods I could find were 300mm which I know would be a little short for a full 300mm diameter print area. I get about 260mm. dc42's suggestion for 350mm rods on the XL (in a different thread) is correct. In fact Repetier Firmware won't let you exceed 260mm thanks to it's safety calculations (I know I can push it further FYI but it gets a little sketchy and I've had the rods explode out pushing it past 260mm on certain movements before)

Calibrating this monstrosity is quite a lot of work, smaller diameters are more forgiving to calibration errors. I used dc42's Least Squares Regression Delta calibration model and once I purged my EEPROM and reset the autolevel and chose 7 features vs 6, I reached convergence quite quickly. With only using 6 features I had issues with the space between towers being higher than at the towers pretty consistently and could never get below an RMSE of .5. Once I had the rod length feature added I got down to .05 in three passes.

I have an old Raspberry Pi B mounting to the side getting 5.1v from a LM2596 based DC-DC Buck. That module is in it's own little T-Slot case on the inside.

Here's a few pics:

Initial Build:

Initial Print (Desk Garbage Can):

Initial Print in Action:


Finished Print:

Layer Close Up(Just fantastic layer registration, until I switched my franken CoreXY to TR8*8 leadscrews had the best out of all my printers)

Fitting the Heated Bed and top cover(I messed up cutting one of the angles sigh, off by 15mm):

Re-doing the wiring and installing the power supply:

Mostly Finished:

Initial fitting of the Raspberry Pi B based Repetier Server:

I have successfully printed quite a few things now, I'm monitoring to see how well the final calibration holds, and if I need to use Repetier's autolevel routine to keep things there. My only issue with the switch based probe is that the "Bend" correction of the probe is quite different based on where it's probing, the way the probe works on Maso's effector variant doesn't trigger properly in a lot cases. I've managed to calibrate the three probe points for the autolevel routine in Repetier but it's not exactly ideal.
Re: Cherry Pi III Is Available
February 28, 2017 06:59AM
Was wondering what firmware to run on cherry pi as havent upgraded my for a year or so and wanted to add inductive sensor.

I run the latest Repetier Firmware, it has a few issues I've noticed like small stalls when I print from the Pi based Repetier server. I've mostly resolved those by changing my serial port speed to 250000. I have the switch based probe but I don't really use it. Even inductive probes in my experience aren't very consistent. On my CoreXY with a 3mm aluminum bed it can be off by 1mm which is crazy. I only use it as a Z min now and have manually leveled it. CoreXY's are louder than a delta but once you calibrate them they don't really move too much. Especially if you have dual Z screw.

dc42's IR probe seems far more reliable to me, I haven't used it though but it seems that it would be much better.

I'd say unless you are running the Duet with the IR probe it's probably better to manually level a delta using dc42's least squares regression model. And use 7 factors vs 6 I couldn't get RMSE below .5 until I did. On my Cherry Pi XL my RMSE is .05 and that's still too high, so I still have some work to do. I'm hoping that getting to 0.03 isn't too onerous.
Re: Cherry Pi III Is Available
February 28, 2017 07:00AM
The length of the spring isn't too relevant, you make up the length with Spectra. The spring just needs enough force to keep the rods from popping out.
Re: Cherry Pi III Is Available
April 13, 2017 04:31PM

its been a while! smiling smiley

My Chery Pi 3S is still running, but I was wondering if there's any carriage with belt tensioner? I don't like the squezzed screw system smiling smiley

- Sebastien Plante (nka)
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