Thursday, 23 February 2017

Finishing touches

Software is hard - it is a never ending task, and if the specification is open ended, as is so often the case, it is really hard.

I have some (paid for) 3D printing software. Simplify3D. It is good, and works well with the TAZ 6. It shows one of the issues with software quite well.

Largely due to the fact I have been ill for two months I got a new 3D printer to pass the time and avoid real work a bit. It really has been educational.

The Simplify3D software is quite good, and not a bad price, but I have already had to make a few suggestions. It will be very interesting if they take them on. Here are the main ones...

  • The first layer of a 3D print is crucial - heated bed or not you need to ensure it sticks. The TAZ 6 is lovely, but even that needs help. I found there were loads of things I could adjust - make the print extrude wider or higher, do first layer in 0.4mm. All these seemed an annoying compromise as they changed what I was printing. What I wanted was the first layer to simply lay down more plastic. Well, they are flexible enough you can - by making two print processes, one for 0-0.2mm, and one for 0.2mm onwards, and the first can do say 1.5 times normal extrude. What I would like is one process and a "first layer extrude multiplier" option, please. They did not seem to want to change this, shame.
  • The "top" layer when it does not meet the edges can mean that it is printed in thin air over the spares infill (see picture). This is something Makerbot slicer gets right (mostly). They did not understand, but I have sent them pictures which may help. I hope they fix this, even if a config option.
  • Bridging (spanning a gap over thin air) needs to have something on which to rest, and they currently only cope with it going to the edge of infill and not over even the inner perimeter layer  - so you can find the top of a thin walled object has bridging that falls through. They seem to understand that one and are considering a change.
So, one of these three I would work around, but there was more.

I would have really liked some carefully tested settings for the TAZ 6. They have a TAZ 6 Single extruder profile, but it has ABS and PLA, and that is pretty much it. They do not have things like ColorFabb PLA/PHA, or Monsterfill PLA, or ColorFabb nGen, ColorFabb XT, ColorFabb XT CF20, or so on. I have had to spend hours making all of these profiles and testing them.

Do they have a forum for people to discuss and share these profiles, maybe that is the answer?

Now, this is  double edged sword. The fact I can in fact make the profiles is really good - I can fine tune the software massively, and this is great, but on the other side - why was this not done for me already (a paying customer)?

Then there are some real sillies... Like when the job finishes the print moves back (out of reach) while the bed cools, and then forward. Cura does the same. This is sensible, as taking off the bed before cool is, well "not cool", and (a) hot to touch the bed and (b) can result in warping the base of the print really badly. When cooled, it moves the bed forward to present the print to you. Excellent.

Except, during this time the hot end is cooling, and some plastic oozes, and then that hits the print as it moves forwarded, either impacting it in some way or sticking to it, messy. Simply moving up a bit at the end of the print is so simple a fix for this, so why not in there?

Thankfully (why is this not already the case?) if you can work out gcode, you can change it, as I have. Now the head goes up 10mm in the process. It also pulls back 1mm on filament before cooling to try to avoid the ooze.

Similarly at the start, there is a point after bed levelling where it waits for nozzle and bed temperature, and oozes, you then print, and this can leave a lump of plastic dragged around. I found on ColorFabb nGen, which can be quite sticky, this ends up in a mess on base of the print. A simple fix is 50mm of slow straight line extruding on the edge of the print bed at the start (like a Makerbot does, actually) to ensure we are extruding cleanly and any ooze is caught up and out of the way. Again, a bit of gcode to fix.

Once again, why do I have to mess with the gcode when it is obvious, but once again, heck I can mess with the gcode and fix this myself without raising a ticked and waiting... Yay!

I really do see how this equates to a lot of software, and putting "fixes" in the hands of the users works both ways. This is a great way to make the users responsible for the fine tuning, but it is important to also try to get the defaults and starting points as good as you can... A lesson for all of us in software.

1 comment:

  1. I use slic3r for mine and it does basically everything you ask for automatically it is very very easy to adjust yourself.

    Setting up the profiles is a bit messy but most printers have some already produced as a good starting point.
    And being free you can excuse having to do a bit of tweaking yourself