A Parallels Rack in Fusion and Sindoh with free Spagetti

Some time ago I made a rough and ready wall mounting rack for my parallels so they would sit to hand adjacent to the Myford manual milling machine.   I used double sided printed circuit board for the construction and while not elegant it worked OK …. until after I had finished it when I found two of the set lurking in a box with a half finished job.   I had not allowed for them in the construction and being OCD me, it annoyed me to have two lose ones that did not fit in the grand order of things.

An idle half day lead to a Fusion design to replace the tired old PCB disaster.  This lead to some thinking on how to design it.   I wanted a rack that sat on the tooling board with the parallels stacked on it with a slight upward angle to keep them in place.   I chose therefore to draw it slightly strangely with the ‘back’ at an angle and extruded it accordingly.   See below.








All well and good you might say.  Less messing with angles etc.

I squirted the job into the Sindoh 3D driver software and then tried to be clever and print it with the backside down on the printer bed …. or at least what I thought was the backside down.   You will no doubt spot that that this is not a simple rotation of 90 degrees but I didn’t.

The printer began producing spaghetti that was not bonding to the printer bed.  After three re-tries I took a closer look at my design and realised that the only part of the job that was in contact with the bed was the leading edge (red arrow below).  The rest was airborne at an angle all due to the way I had chosen to draw the object and rotate it.

Reset brain and reset printing so it would be now vertical.   All was good and my nice new rack sits on the tooling board.

A little bit more brain engagement next time perhaps ?

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French Tablecloths and Fusion 360

OK this is a silly one I know but follows on from my theme of just how valuable a 3D printer is to own and how it makes you think outside of the conventional box when solving simple problems.

French markets always have a stall selling brightly coloured table clothes in various materials.   These rarely have a prepared hole in them for your sun umbrella to slot through as you sit quaffing and nibbling in the sunshine.   If they already have a hole it usually doubles the price.   If you make a hole yourself then it will fray and degrade.

Up steps “Fusion Man” and in five minutes you have a design for a locating boss and ring to sandwich protect the hole in the material and keep the cloth fixed on the table.   Design done and its off to the Sindoh 3DWOX to print it.

Lay the table cloth on the table where it will be used and ensure it sits square all round.   Crawl under the table and with a Sharpie pen or similar, draw the shape of the hole on the back of the table cloth.

Remove the cloth from the table and flip it over.  Place the printed ring over the marked circle and remark the circle position to the ring ID.  Cut out the marked ring circle but make the cut about 3 or 4 mm smaller all round.  (Nail scissors are ideal for cutting curves).  Test fit the boss. Because the hole in the cloth is slightly smaller than the boss diameter, the material will naturally turn up the vertical face of the boss.  Check it is not causing wrinkles in the cloth when on the table.

Put hot glue around the boss at the horizontal/vertical interface and then push the boss through the cloth to let the glue hold it in place.

Apply glue to the locating ring and push this in place over the boss to sandwich the material between the ring and the boss.  Here is a greatly exaggerated cross section.

Job done.   Siesta time.

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Open Thinking when Solving a Problem

I think I have mentioned this before …. when you have different ways to solve a problem it is often easy to get locked off into a long winded but potentially elegant solution and miss the point.

3D printing has brought this home to me on a number of occasions.

An example – I have variable speed controllers on my Myford Lathe and Myford mill.   The controllers are identical and each have an ON and OFF push button.  The bezel around the ON button on one of these had cracked and come away leaving the switch floating in its mounting hole.

My first reaction was to replace the switch.  I contacted the controller supplier to ask for a part number and distribution source to buy a new switch.  They ignored my email which was fortunate as I would probably have ordered a complete new switch assembly.  I would then have had all the grief of stripping down the controller case and wiring in the new switch.   This would probably have invalidated any warranty etc etc.

Instead I stepped back and looked at the problem from a different angle.  The bezel while broken still had enough of the ring and thread intact and simply needed gluing back together.   However it would not have been strong long term.   What it needed was an outer strengthening ring.

Fusion 360 called and the Sindoh 3D printer.   A ring was designed and printed  (20 minutes) and the bezel strengthened and made good.   I also printed three more rings and put these around the remaining three switch bezels as a preventative action should they also weaken and crack.

A simple, low cost and effective solution with the added benefit of reduced downtime in the future.   But the point is that it wasn’t the first solution I was considering correct though it might have been.

3D printing is such a useful resource to have available but you need to think outside of your normal approach to a problem to realise its potential.

Sorry that wasn’t mega interesting but I thought it worth sharing …

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Finishing the surface of 3D Models

Over Christmas I had 3D printed a clock frame for my granddaughter’s birthday.   The size ended up being three separate prints which I later glued together.  All three prints were done ‘face down’ on the Sindoh bed and all printed on a raft.   Once the raft had been removed the finish was not very elegant as it showed the striations of the raft on what would be the viewed surface.   The print was in PLA and I initially did some tests on scrap prints to see if I could rub a surface down.   This was not an ideal approach and I was not too keen to start on the clock in this manner.

Next idea was to use Gorilla twin pack glue cut with Meths.   This created a very runny adhesive mix that could be brushed onto the surface of the print.  Surprisingly enough despite being ‘modified’ the glue went off and was quite hard to the touch.   It did not rub down all that well.

Reading up on the net there is a product called XTC-3D which is made just for this purpose.   It is expensive but does stretch a long way in use.  It is a twin pack mix in 2:1 ratio and once mixed it has a setting time of around 20 minutes so you need to get your act together and be well prepared. The makers recommend using a wide foam brush to apply the compound.   This was quite good in that it ‘scraped’ across the tops of the striations and the filler settled like levelling compound does on a floor.

I left it to harden off overnight and then rubbed down wet with 400 grit paper on a flat surface.   This kept the dust damped. The finish was excellent.   I then undercoated and glossed with acrylic spray paint.

The final clock frame looked very good with no obvious signs of the printing artefacts.  While pricey, I would recommend the XTC-3D product for this purpose.

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I’m not saying our kids are alcoholics …

But this was a nice exercise in Fusion 360 and Sindoh printing and provided some simple UNO winner prizes.   (Yes we always play at Christmas and it can get very bloody …).

The challenging part was wrapping their names round the body and I am indebted to John at NYC CNC for his video on putting text on a cylinder (Fusion Friday FF104).  Editing the names was not quite so simple – the clue is to turn the body off so you can get at the text which sits in a different plane.

Happy Christmas to anyone who reads my stuff.  More in the New Year and hopefully less Haimer probe breakages.

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