View Full Version : So, what am I missing?

24-02-2014, 06:51 PM
Ok, I've got the following parts...

a small, fully working, calibrated CNC table,
a 0.3mm 3d print head,
a roll of 1.75mm PLA filament,
a pid temperature controller,
a psu,
a drive unit for the print head motor,

I have downloaded a sample .slt file of a nut and run it through Slic3r, this generated g-gode that looks suitable for my Mach 3 setup.

So, if I fit my head to the table, wire up the Pid controller to the psu and hot end, calibrate the extruder feed, set the head to zero on the table and run the code, what am I missing?

i know there are a million variables to fine tune, but have I missed anything vital before it gets messy?

Does printing start at ground zero or should the head be raised an amount, if so how much?

i know about glass beds etc but for a first run, surely a sheet of card would work just to squirt plastic on?

24-02-2014, 08:40 PM
You want the head about half the slice thickness off the table (I'm assuming sli3er has used 0 for the first layer height) - this squashes the first layer down firmly.

The head needs to go on the Z axis - I assume that was a typo :-)

You can use some masking tape to print on - maybe on some MDF - cardboard might be ok but the first layer height is quite important.

If the part is small you will need a fan (start after the first layer is finished) otherwise the build up of heat will melt the object. This can just be a desk fan or you could blow on it :-) Alternatively you should be able to tell Sli3er to dwell between layers but a fan works better. Alternatively print several objects. The problem is lost plastic oozing out during the dwell.

Good luck - when it's working it's better than watching TV :-)

24-02-2014, 08:56 PM
Brilliant, sounds like after a bit of wiring and fiddling I should be ready to get messy :)

i'll post some pictures of course.

24-02-2014, 09:28 PM
If you take a look around, there are a number of sample files of test objects (thingiverse.com is a good place to look). Classic starting objects are simple cubes around 25mm on a side which are useful for checking print quality, calibration, etc. I agree that cardboard isn't a good surface for testing as it is unlikely to be flat enough - if you are aiming at getting the first layer extruded with the nozzle at half layer height above the bed, which is a good starting point, then that's pretty demanding on flatness.

They are indeed fascinating things to watch!

25-02-2014, 11:52 AM
Hi Davek0974

Can you list where you got the components listed in your first post from.

I'd be interested in trying this on my CNC router and see whether the parts are something I could package into a format that would slot in place of my spindle.