0.5mm Slots

Hello,

I recently got my TAZ4 and have got the hang getting some plastic down. I am trying to print some electrical connectors that have a small slot in them 0.5mm x 3.0mm. I have played around with orienting the connector in a few different ways and turning the supporting structures on and off, but the slots are either way too small or non existent. In my opinion some setting is wrong and its acting like it can ignore any feature that is below 1mm in size.

I’m printing with ABS and the 0.35mm nozzle. Am I printing it wrong by having the print start on the purple face?

Any advice would be appreciated.

You are going to want to print some calibration test pieces and really get your extruder dialed in, filliament diameter perfect, etc. before you can print an opening that small reliably. I’d try grabbing some of the dimensional print calibration test prints from over on thingiverse, run though them adjusting as needed in filliament diameter and extrusion modifier until you end up with very close dimensions.

Oh, I forgot to mention I also have the 0.25 and 0.15mm nozzles. Should I make the nozzle change before I do the calibration prints?

you should use the one you plan on utilizing for the final prints. the smaller ones will print finer detail, but take longer.

OK so I followed the Instructions on the OHAI site to calibrate the extruder.
http://ohai-kit.alephobjects.com/project/extruder_calibration/

Then I measured the filament diameter and got a good average, and loaded the slicer medium profile from the lulz site.
I adjusted the filament diameter in the profile and made a print. My part is 28mm x 7mm X 11mm tall. I’m measuring it to be 28.10x7.25x10.80. Which is close enough for what I’m doing, also I feel this could improve going to the slicer fine profile.

The problem is still the slots. I watched the printer outline them on each layer and then come back and fill it in. Almost like it thought it had to infill that area. Moving along the X axis it would make seven small slots and then came back and do seven y axis extrudes filling the slots. It did this on every layer. Any thoughts?

I’m tempted to oversize the slots and try again.

Oh random question. I have a 0.35mm nozzle installed, but extruding natural ABS into air what should the OD be? If I measure it I’m getting 0.56mm not 0.35mm.

If its a 0.35 nozzle then it should have a 0.35 hole? Which means I should have 0.35 plastic? Does ABS have an expansion rate that needs to be calculated for, or do I have a miss labeled nozzle?

Plastic does have a shrinkage factor to account for as it cools, but it’s a fairly small amount. I just meausred a piece of cold extrusion from my .35mm nozzle that has been sitting there for a few days, and it measures in at 0.36mm to 0.37mm along the length. It’s just leftover ooze from the last print job, but it’s still fairly close. I’d almost guess you have a .5mm nozzle installed somehow, which would be odd since almost all of the TAZ’s shipped with 0.35mm nozzels. It may be worth removing the nozzle and checking the bore. If you have one cut wrong customer support should be able to get you taken care of.

Any filament extruded in the air can be subject to what’s referred to as “Die swell”: http://web.mit.edu/nnf/research/phenomena/demos.html

It’s normal for these kind of things. The extrusion diameter (in the air) can be changed by manually exruding faster or slower, but in our application, it doesn’t really matter, as your extrusion speed when printing is determined by your slicing settings. Your nozzle should have .35 engraved on it and should be fine.

Your hole dimension might be too small for the slicer to consider real, I’d make it bigger and then mic the result till I got it right, your print orientation is correct but could be Z mirrored to make the small holes printed lastly on top. When I make dimensions/features too small the slicer fills them even with the extras (such as add extra parameters) turned off in the program.

I noticed a tiny bit of extrusion foot on the base layer (slicer default set at 200% extrusion flow for layer one) this may be why you’re filling such small holes but if it is actually going to the hole location and filling it, then you have a setting wrong somewhere, you need to regenerate the G-code when setting up multiple parts printing, the code can get messed up sometimes and extra planes and layers can be added where they shouldn’t be, I have seen this using slicer when printing multiple parts. After re-doing the G-code they printed normally. You can view the model and how it will print in pronterface, which can show if the model got corrupted during G-code generation before printing.

Thanks for all the information guys.

I’ve made some progress and just about have it nailed down. The one thing I haven’t figured out yet is why are my prints coming in at 0.10-0.20mm oversize? The length is 28mm and I measure 28.23mm.

Looking at the picture here you can see the evolution and how I’m getting better.

#1 is with 2.89 filament dia. Beginner settings on slicer
#2 is with 2.85 filament dia. (speaking of this how constant is this number supposed to be? This roll of natural abs I have bounces from 2.83 to 3.19)
#3 2.85 filament, medium slicer profile and I increased my slots to 0.75mm. (at this point I could see the printer making the beginning of the slot on the first layer, but by the time it has reached the top layers the slots have shrunk or filled in. Any thoughts on this?)
#4 same filament, medium slicer profile and increased slot (0.75mm). I changed the orientation of the print. I laid it on the side so the slots would have to be printed horizontally.(The red arrows indicate which side was touching the glass) This seem to work the best for the slots, I just need to add in some more supports for printing the over hang.


Any advice on what to try next?
Fine slicer profile? Or smaller nozzle? (I have to 0.25 and 0.15)

I’m still curious on how this machine/software accommodates for die swell. Yes slicer controls the extrusion speed, but how is slicer calibrated to know that a given speed equals what die swell amount?



Ok, so I am finally able to get this machine to print slots. I was about to loose my mind over it and decided to print a simple test piece. I modeled up a 1inch cube with 3/8 holes in each of the faces. The over all dimensions of the block were correct and ranged from 1.0000" to 1.0070". Now the holes they were a different story instead of being 0.375" they were 0.3495" to 0.3654" always undersized. So I did some google searching and found out I wasn’t the only person with this problem (thank goodness my sanity was hanging by a thread)
https://github.com/alexrj/Slic3r/issues/1588

So with version 1.1.7 there has been XY size compensation added to the program that will allow you to input how much your holes or slots are undersized and it will oversize them.

This allowed me to be able to print my slots. :open_mouth: :smiley:

But it is now causing another issue. Lets say I have two holes that are separated by a wall 0.25mm apart and I put in an offset of 0.1mm the effective distance of the wall according to slic3r math just became 0.05 and it will not print it, even using a 0.25mm nozzle. Can anyone point me to a setting that will help me out?

Where is this setting? I can’t find it my Slic3r 1.1.7.