Space Bar, The final frontier

The final hurdle for ‘good enough’ for me now is the space bar.

Every key prints lovely, except the largest one……Take a look

Eeeeew, kinda looks like a ….

I’ve gotten all the ‘hard stuff’ over and done with first, or so I thought. Life’s taught me to generally avoid going for the low hanging fruit first, save the easy stuff for later when you need a boost.

Well, no matter what i’ve done (so far) in 12 iterations, have I been able to get a good looking space bar.

Now this has become my sole focus and roadblock for a successful print

Turns out that this is a combination of quite a few variables, I’ll list a few and probably follow up another time with clicky links and research

  • Exposure times are wrong –
    • They could be , I’ve really just gone and shoved stuff in to print and hoped for the best with standard settings. I Have now tweaked up the settings a little bit to 2.2s per layer due to mixing pigment in, and have had no real failures. I’ve also increased the first layers exposure times to 30s, still seeing minor issues there
  • FEP tension is wrong
    • Not really, This is a brand new printer, i’ve had zero catastrophic failures and have been overly cautious monitoring (and catching) early delamination from the print bed issues – Three times now
  • Bad Resin
    • Possibly. I’ve 3 types (all anycubic) and seeing the same on all 3
  • Temperature
    • Possibly, lots of people have been reporting issues in cold climates, I use the printer in the conservatory and it’s sub 10 degrees C in there regularly
    • Low temperatures cause increased viscosity and warpage issues with fine features from the FEP pulling them through the thicker resin
  • MY FAVOURITE
    • Exposure –
      • Too low exposure times on fine edges cause resin to cure, but not as hard as it should. So, when the layer sets on the bed, when it’s pulled off the FEP, it warps as it’s soft. This, I believe is causing the sagging issues i’m seeing on that space bar – it’s printed upside down, so the supports hold the points up, and between the walls sag, like an electric line held between two pylons

My solution……

Probaly waaay too many supports, but this way, each ‘sag’ will be between supports that are just 1mm apart.

I’ve also nearly doubled the wall thickness to about 1.8mm – from 1mm

Blue lines show original thickness, gold shows it doubled

Hopefully now, this is the last step, Colour’s good, CAD is good, Supports are good.

I’ve ordered 2 Litres of clear resin ready to go and have a colour that’s not exact, but close and, importantly , very easy to re-create

Resin8 Earthy Brown, 3 ‘blobs’ of the end of a lollypop stick to 100ml of resin. and Black, 1 blob.

– The Rich brown used previously was too red. I’ll experiment a little with more black when running off the final tests

https://www.resin8.co.uk/opaque-resin-pigment—earthy-brown-7468-p.asp

https://www.resin8.co.uk/opaque-resin-pigment—black-2383-p.asp

Coming soon!, more kits in stock, and Keycaps – March 2021!

Author: Bleugh

Early Fourties, Wife, two kids in primary school. Both of us work full time...3 years now Back in Blighty after a decade away...It's a new country for everyone! Still finding time to tinker!

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