Evolution of a Blog

This blog has evolved as you can tell by comparing the title with most of my recent posts. The title should really be something like "The Physical Interface Side of Computing". Actually, more recently it would be "3D Printing and all of its Trials and Tribulations". Anyway, it will still feature Raspberry Pi and Arduino from time to time but my current hardware of choice are a Wanhao Duplicator 4S and an Ultimaker 2. Just before that it was a BeagleBone Black with JavaScript and Node.js providing the development environment!

Thursday, March 13, 2014

Random / Occasional Axis Slips

My printer is in it's terrible twos.   It went through a period of printing stability and still has its moments.....until an axis decides to randomly slip or skip.  I have been working on this for weeks and have tried everything that I can find on this board (at least I think)!  As I said, the printer will have moments of stability where it will print for hours with no issue and pretty good quality.  The X-axis is the favorite to slip but the Y and Z will occasional join the fun.  It does not always happen on a long print as it has been known to happen early in a print as well. 

Here are the things that I have tried and/or ruled out:

I have adjusted the trim pots from just over stall to a quarter or more turn past stallI have swapped stepper drivers
I have moved the x-axis to the second extruder slot
I have upgraded power supplies
I have added a big cooling fan to the electronic stack
I have ensured that my timing belts are not slipping
I have made sure that the carriages move with minimum resistance
I have slowed everything down when I slice the part

 What else is left to try?!?!?   Could it be the Ramp board ... or the Arduino?  They are the only things that I have not replaced or been able to rule out!   Frustrating!

One thing that occurs to me, that is easier to remedy than a swap out of electronics, is connecting the printer to a cleaner power supply.   I just happen to have one (that also converts from 220V to 120 and offers filtered power at 220V) so that is in the circuit now.

Someone on the RepRap Forum has suggested possible EMI issues, if not in power, then I don't know how I would solve!?!?

[Update] I have gone ahead and replaced the Ramps board and the printer has been behaving since including finishing a seven hour print with no hiccups.   Fingers crossed.  

[Final Update] Printer has been stable.  It was either the Ramps board, or possibly, a wiring fault that got corrected when I replaced the Ramps board.   Not sure if I will ever know!


  1. Hi,

    I was wondering if you could help me. I have the same Prusa i3 kit as you but I am a little lost. It talks about a heat bed thermistor, but I can't seem to find that in the kit. Did your kit come with this or did you have to purchase separately?

    Thanks for any help

    1. It came in a little envelope and looks a lot like a capacitor but is a 100K resistive thermistor. It is not already mounted on the underside of the heatbed by any chance is it? If not you may be a victim of poor parts quality control. They are readily available and not real expensive. Here in the UK I was able to get one at a electronics store called Maplin to replace one that went bad. Couple quid.

    2. Thanks for replying. Yeah it seems that I don't have it, so I've ordered one from a local supplier. It came with these things that look like resistors (shaped like --o-- rather than ==o), but I don't think they are the thermistors. This is my first kit so having a bit of an interesting time putting it together. Your blog has helped.