The K8203 direct drive extruder kit

Hi there this is a question for the Velleman engineer’s why is this product not working i myself bought the upgrade and have not came close to getting working and as the form goes i have not seen anybody saying they have got it work. I cant get the extruder motor to run it chirp and chaps but no reel flow to me the spring is far to tight with know way for adjusting it, someone suggested to grind the top ring off done this but still not much of an improvement i cant print with this i just cant seem to get it right.
Can i ask you why you released this product with these problem’s you must have had similar problems everybody else has. and the bit that is really annoying is the price £91 pounds, cmon you must step up to the plate and sort this problem out.

Honestly I’ve to say not to be happy with this upgrade as well.
After nights of investigation, plenty patches and multiple unsuccessful prints, I’m now able to create parts.

But a very disturbing and annoying problem is the irregular/pulsing extrusion due to the direct drive approach. Therefore I do not have smooth walls and everything looks fluffy.

A direct drive extruder is more precise to give exactly what is asked for from the electronics so basically every stepper pulse shows up on the print and is visible as moire. It really drives me crazy but I’m not able to tune the Z-stepper for a continuous movement.

See also:
soliforum.com/topic/4759/new … -problems/

You’re right, 90 euro’s for a kit containing a stepper driver and some metal parts is really too expensive given the poor results. Normally I am very positive about Velleman kits, but this time the advise is: do not buy.

I’ll add my voice here as well.

I have been using a pair of K8203’s for a few months now. When this extruder is working correctly, the results are amazing. But, like others here, I have been frustrated by periodic failures of the extruder characterized by a clicking sound as the extruder kicks backwards.

Fitchie posted some excellent information about his research into the stepper drivers, and his conclusion that the 1/32 microstepping might be too aggressive for pushing the filament. His recommendation (which I have tried) is to reduce the microstepping to 1/16th to ensure adequate torque to avoid kickbacks. This seems to help the situation, but will have the effect of making the extrusion less smooth.

On my printer I had used 0.9-degree stepper motors instead of the stock 1.8-degree steppers. This effectively doubles the stepping resolution, so my extruder running at 1/16th microsteps is producing the intended output resolution. My printer does not exhibit the moire pattern that Fitchie reports.

My 8203 is now working very well. Print quality is the best I’ve ever gotten, and bridging is working better than ever. But I still get occasional clicking when printing solid layers at full speed. I found that placing my hand on the extruder motor while it prints these areas keeps the motor cooler and seems to avoid the problem. This makes me think that adding a heat sink to the motor would keep the motor cool enough (and keep the current draw lower) to let it power through even these parts of the print job.

So my conclusion (based in part on Fitchie’s investigation) is that the K8203 is right on the edge of being able to generate enough force to push filament under all conditions. Perhaps a stronger stepper driver is needed, or some kind of cooling solution for the motor itself.

The direct drive extruder is a great upgrade when it works. It is definitely worth the effort. I hope everybody here is able to get theirs working to their satisfaction.

Hi there thanks for the reply’s it’s a bit disappointing that know one from Vellemans has said anything there response would have been interesting, they obviously have seen what is happening to everyone who has bought this upgrade, I have yet to read a post where the person has fitted the new extruder and not had any trouble’s. You know when i saw this upgrade for sale i jump at it thought this would have been a good move but no such luck.
The part that confused me is why there was fittings for right hand one and left hand one in the box??? why and what did this add to the cost???
other company’s dont give both right and left they just give you one that works.
At Velleman’s do they not have to supply goods that are mercantile quality and fit for purpose because to me £91 was a hefty price for me to pay for an upgrade that does not work, and still know one from Velleman’s has come on to the forum put their hands up and said we have got it wrong and either sort it or offer us a refund.
I would not recommend to anyone to buy this upgrade it simply does not work

Another thing i could not get to work is the pla firmware i just could not get repetier to except it I am using the VELLEMANS CUSTOM SOFTWARE.
And this does not help.
Is there anyway you could put the settings manually and perhaps save the settings.

! have just spent another night working on the k8203 extruder, as said in previous post i could not load firmware for the 1.75 pla so i used the latest version of Repetier ver 1.6.1 and suprise i got the new firmware to load so i tried to print the 40mm cube and it has printed and the finish on it is really good if someone can tell me how to upload a picture i will.
I have measured it with digital callipers and it is spot on 40mm x 40mm x 40mm. the only problem i have now is that the step motor is ticking and is inclined to heat the motor i think this must be the step setting but i have know idea as to how i can change this or should i just try it with the A4988 driver ??? if i could get rid of this clicking i would over the moon with extruder.
I would even recommend it to friends if they want to be bothered with all the tinkering.

i636.photobucket.com/albums/uu87 … CF4175.jpg

Forbesbrb Glad everything is working now.
Dr. Vegetable you said you are using a pair of K8203s
Are they on the same machine (dual extruders) if so what control board are you using? or are they on separate machines.
I really like the K8200 it has been the most frustrating fun I have had in awhile and to me it’s worth it.

[quote=“Wrong Way”]Dr. Vegetable you said you are using a pair of K8203s
Are they on the same machine (dual extruders) if so what control board are you using? or are they on separate machines.
I really like the K8200 it has been the most frustrating fun I have had in awhile and to me it’s worth it.[/quote]

I am having a lot of fun with this kit as well.

I have a pair of 8203’s mounted on my dual extruder machine, which uses an Arduino MEGA 2560 and a RAMPS 1.4 shield to provide the needed 5 stepper motor channels.

All of your questions have probably been answered in my post about that mod. If not, just ask. ; )

See: viewtopic.php?f=53&t=16560

Thanks for the information.

Hi there i have a new problem yesterday i was printing and it has started to skip on the y axis i stopped the print i started a fresh one this time it has skipped on the x axis i dont know what s to cause of this i have checked the belts they seem tight enough i also checked the voltage on the x and y drivers they are set ok i did not have this problem before the upgrade.

This is a pure guess.
Did you load the correct firmware.
There are 2 versions for the K8203
1 with the K8204 and 1 without.

i have the ver 2.3 as i have the k203, and k204 improvements i am still get the skipping steps on the x axis i have change the motor driver and set the voltage .550, its the only problem i have with it now i also tightened the belts so they were not jumping a tooth. I am open to suggestion as what else would cause this problem the annoying thing is it doesn’t happen all the time.???

Check the screw that holds the pulley on the motor.
Sometimes they come loose.
Look at the bearing on the other end to see if it’s locking up.

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hi there i managed to print 4 things and would you believe it the extruder body the peek part now i know why it is called peek because when it starts to melt it makes you peek.cry as it is the start of another expensive part you have to replace what i dont understand is i have a fan on the peek part and is on continuous and it still manage to heated enough to let the threading melt and out pops the extruder. the part costs £31 + postage £3.50 total £34.50 I think i have spent enough money now if i had got some to print the parts that printed it would have cost less than £20 but in total it has cost me £91 for the new extruder and now to fix it with probably the same thing happening again another £35. i think it is time to throw the whole extruder in the bucket and perhaps i will just make another prusa i2 and scrap the velleman k8200, it is a product that does not seem to work for long what ever you do and the cost is just getting to the stage that my wife is complaining about the costs. what i cant understand why use the peek it is not fit for purpose the same part can be made from aluminum and probably half the cost in fact i thing i will try and make an alloy replacement look forward to your replies perhaps someone from vellemans might even chuck a solution to us

Has anyone ever tried to alter the original extruder to take 1.75 filament would not think it would be a massive alteration perhaps the hobbled bolt might be a challenge but the rest should be easy enough.

I forgot to say that when the extruder was working i was using the card reader to control the unit it was good but unlike the computer
there was no clicking whatsoever seems strange you would have thought it would have been the same.

Has anyone tried using 1.75mm with the old extruder using this part thingiverse.com/thing:1232958
1.75mm filament block for K8200 worth a look.

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