• Chris Cassar

The no bull guide to 3D printing PART 2

Updated: Apr 20, 2019

Design how things will fit

Separate parts can fit together is so many different ways, take a look at any product you might have in front of you. A designer has spent countless hours working out the most secure and cost effective way to fit something together, they had to think about if it was something that was going to stay together forever or if it was something that you would need to remove occasionally or quite regularly. I have modelled large screw threads on some of my parts which have worked really well for large cylindrical parts, for smaller parts snaps fits are a common go-to for me. There was a great article about different fitting methods where I got some ideas to try some great stuff which I’m using now when we do 3D prints for end use parts. Here’s the article that got me started on a new way of thinking.

https://3dprint.com/27032/metal-threading-in-3d-prints/


Image: Instructables.com


What temp is the right temp?

This can be tricky but at the risk of sounding like a broken record with all the other blog posts, articles or YouTube clips you have watched you need to change the temperatures to suit your material type and brand. I originally used the genuine filament for my UP printers but after getting my hands on the hack to get into some of the printer's settings I was able to start using 3rd party filaments giving more material options and colours, I no longer need to use the hacked version anymore since the new Up Studio slicer. The manufacture of the filament should be able to give you a temperature range which the filament will print with, and considering that not all printers are created equal you will need to do so testing and tweaking. Here’s how I do it… I have a standard model which I use. It's tall enough to give me some space to test some different settings along the print. I’ll load it up, and set my basic start settings. Let’s say I'm doing ABS and i have a new filament that gives me a temperature range of 220-260℃ My model might be 50mm high so what I will do is set my print to pause at particular mm height intervals, (This is a perk to using the UP software) at which time I will change the extrusion temperature and see the effect it has on the print. Let's say I pause my print at 10mm, 20mm…. Up to 50mm, this gives me 5 different intervals to change the temperature, now this is coming from a bit of experience but I will be starting at around 225℃, and increasing to 230, 235,245, and 250 with respect to the "pausing" intervals. What I’m looking for is that small 10mm length where the detail is nice and smooth, the layer adhesion looks like it's a good hold and that the colour of the filament is correct. I might do this more than once and perhaps on the second go look at only pausing it 2 or 3 times to get a larger sample area. My point is the 1 hour of testing you might spend here getting your settings right will save you so much time when you're printing the real thing later.


The first layer and Buildtak.

The first layer of your print is the most important layer, it doesn’t matter if it's a 40min build or a 15-hour build. If your model doesn’t stick well to you build platform you could be left with a wide range of problems; part detachment, warping, layer misalignment, or even jamming nozzles. I still have days where my printers just don't want to play ball with me and I will struggle to get a model to stick to my build platforms to get a decent printed part.

Now I’m a huge fan of buildtak. I started 3D printing with an UP plus2 and these came with metal perf boards that made it a little hard to print raftless. I had tried Kapton tape, painters tape and a variety of other ideas that people had put up on social media and forums, nothing solved my problem like buildtak. Still remember the first time I saw it in action, I was at a 3D printing show in Melbourne and a stall had them on display and they were nice enough to give me a sample to take away to try. After arrive back home and applying it to my build plate I was hooked. I’ve never found anything is good as this. I still buy them in bulk.


Up Plus build plate, Left: No Builtak, Right: Buildtak

For those who don’t want to spend the money on Buildtak's, I completely understand, sometimes you are just not in the position where you can do that. The key things you need to keep in mind are simple and will be specific to your machine of choice.

Make sure your print bed is level; every printer has a different way, but every printer also falters from having an un-level bed, if your model has perfect adhesion on one side and is barely touching on the other what do you think will happen?

Nozzle heights play their part too, once your bed is nice and level you can make sure your nozzle is at the perfect distance from the build platform to get a nice stick. I find using a business card which has a thickness of about 0.4mm gets the nozzle on my UP and my UM2 close enough to “smoosh” the first layer into the build platform for good adhesion, however sometimes I go even closer on the UM2 or if I'm using a buildtak and going raftless in that case a piece of normal office paper does the trick for me.

Make sure your platform is clean, I use a bit of acetone on a clean cloth and wipe over to get all the oils and greases off it. If you're a person who likes to touch your platform to see if it hot enough or wipe something off with your hand then you're going to have to keep cleaning your platform. The oils and greases from your skin will stop your prints sticking down.

I hope at least 1 of these points helps you along your way to 3D printing success.

Chris


Add threads to 3D printed caps. Printed in ABS

23 Johnston Avenue, Haywards Bay, NSW 2530, Australia

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