Mendel problem with printing

Hello Everbody,

I experience problems when trying to print. The ABS doesn't stick to the ground plate.

I have:
*Mendel
*Techzone Remix Electronics, Generation 3
*The extruder that comes with botmill kits (geared, one big one small)

I think the problem(s) could be:

1. The extrusion rate is too slow. What is a normal extrusion rate? I've seen a video of a Bowden extruder wich is very fast. Mine can do about 10mm/s best @225 Degree Celsius. The ABS is from the German Reprap Foundation. Does anyone have a hint?

2. XY-Speed is too fast. The Mendel axes really move fast. I experimented with Skeinforge instead of Mendel software to generate gcode and it was moving very slowly. How can I set the speed in the Mendel host software? I tried some setting s without effect.

3. Z Home height. The Extruder Nozzle is about 0.5-1mm above the ground plate. Varying this didn't help though... Is there a rule of thumb?

4. Heating too weak? I have a 6.4Ohm NiCrome Wire. I now found suggestions of 6 or less ohm to be better. P=U^2/R, 144V/6.4Ohms=22.5W should I decrease the heater wire length to get more Power?

5. Would a heated bed do the trick? Or is this for rather for big parts? I tried to preheat with a pan of boiling water. No sign it was better...

Maybe you have better ideas or you could give me an idea?

Thanks
Daniel

PS: Never try to run the host software or Arduino IDE in a Virtual Machine I experienced USB communication Problems with VMware and Virtualbox, gave me quite a headache... Or first make sure you are not affected.

what material are you extruding onto?

There are four critical factors: HEIGHT, SPEED, TEMPERATURE and SURFACE.

HEIGHT: Above the bed. This is the most critical aspect. As little as 0.1 mm can make a big difference.
SPEED: Low and slow as opposed to high and fast. With Skeinforge you can set different settings for the first layer. Make it much slower e.g. half as fast.
TEMPERATURE: ABS and bed are both important. With Skeinforge you can extrude the first layer at a higher temperature (maybe as much as 10°C higher) which makes it stick better. And the last factor is the temperature of the bed. With a cold bed you will have problems. You can warm it up with a hair dryer but the best solution is to install a heated bed. This will fix your sticking problem and also allow you to print very large objects without warping.
SURFACE: For ABS kapton tape seems to work well for most people. For PLA glass or blue painters tape.

Use Skeinforge!

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Not said yet.. but if you want to stick ABS to Kapton.. you need up around 100 degrees C surface temperature... less than 80 deg C and you won't stick...

If you want to Stick ABS to Acrylic,then lower temperatures required.. (room temperature).. but you can only make small objects due to warping.

Al...

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[araspitfire.blogspot.com]

rhmorrison Wrote:
-------------------------------------------------------
> There are four critical factors: HEIGHT, SPEED,
> TEMPERATURE and SURFACE.
>
> HEIGHT: Above the bed. This is the most critical
> aspect. As little as 0.1 mm can make a big
> difference............

>.................... SURFACE: For ABS kapton tape seems to work well
> for most people. For PLA glass or blue painters
> tape.
>
> Use Skeinforge!

this is the advice(i think from the same person) that got me back sticking. from my messing around id say these are the 2 key points. and sometimes i jog my z axis a little with just my fingers to get it to move those tiny bits between too low and too high(TINY changes can make or break the whole thing)
thanks
brian

Hello Reprapers,

Thanks for all the Answers!

@mlagana: I tried to use some painters Tape and the alu bed directly.

@rhmorrison&araspitfire:
I'll definitely buy a heated bed and use Skeinforge. When I've set it up I'll redo the Z height adjustment.

I'm looking forward to my first prints and will let you know about progress after my holidays

Cheers
Daniel

ABS will not stick to aluminium at any temperature and also not to cold painters tape.

To make ABS work without a heated bed you will need to use a raft and a bed material it will bond with. Acrylic, Foamex and double sided carpet tape are know to work.

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[www.hydraraptor.blogspot.com]