Friday, 13 February 2015

Winter Project ...

Thing 582366 by Huxley #710
With the onset of winter thoughts turned to heating bills and trying to keep them down. Most time recently has been devoted to writing code on a Raspberry Pi for my Honeywell Evohome central heating system.

I decided to print a case I had seen on Thingiverse which had some interesting design features I was looking forward to trying out for my self.

Later Edit - Natko decided to take this design down from Thingiverse. This in turn seems to have destroyed the record of my make. A support request has been posted with Makerbot, I will post on this later. Fortunate I keep my own copies of images I post and the feedback left for the make. These are below, I also have all the STL files as well.

Printed on Huxley #710 using 0.25mm layer height. Slicing by Slic3r Rev 1.20 (edgy). I have a better retraction in Slic3r setting now so blobs greatly improved. Faberdashery filament, white and black.

The ribs inside on the lower half printed wider than the allowance / clearance on the upper mating half. So 1.50mm on the design came out as ~1.65mm due to bead thickness. The result is the lip on the bottom half will not immediately engage with the upper mating half as the post are nice and stiff. As there is a friction grip on the posts with spring action. I might have been tempted to create more clearance for the lower lip, to allow for manufacturing tolerance. Currently the design has it at around ~0.10mm clearance. This is quite a tight tolerance, for any (plastic) part and along a length of ~60mm, exciting.
Thing 582366 by Huxley #710

Some relieving of the posts with a craft knife and it snaps together satisfyingly snugly.
I wasn't sure that Huxley #710 would cope with the lower half overhang design, it seems to have worked well.

The break off supports worked a treat, that's why I included a picture of them, as I wanted to better understand the performance of this type of support. The feet recesses faired less well and without destroying the case these are on for good. I suspect more vertical height is required on the break off although a cooling fan might have helped as well.

I do think the case is ~7mm longer than absolutely necessary as there is a lot of clearance around the SD card to the edge of the case. Could be the design accommodates some feature I don't know about such as an expansion board or longer SD card.

Love the LED pipe / shield.

Nice design, better than the commercial case which felt flimsy at £4.50, for my Evohome temperature logger.

Meanwhile, as the winter progressed it was noticeable that quite a few windows in the house were not correctly seated in the frames. Wind in the autumn was howling through! There didn't seem to be the adjustment expected to cause the plastic frame to be pulled into position correctly. Inspection in the window frame jamb revealed a number of wedges, intended to push the window against the elastomer frame seal. It seemed clear these were not at the correct height. I could have printed a flat spacer and popped it under the original. However this would have meant the screws would not have the correct engagement. Additionally the whole item would be stood off more into the jamb and potentially fouled. I suspect the fitting kit for the window had different size wedges available. However we were never supplied any with the house. So I measured an original part and increased the wedge face height by 1.0 mm. It worked beautifully and having printed 12 of them (2 per frame) the offending windows now seal beautifully against the elastomer seal. All snug and warm for winter!
Window wedge to align and close plastic window into frame to seal

Evohome PHP software running on Raspberry PI

Thing 582366 by Huxley #710

Thing 582366 by Huxley #710
Dec 2015 - Despite further support request to Makerbot in November on the issue of my deleted Thing files, I received no response! Caveat emptor, save your own data and records.