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3D Printing Safeties
Well, today I had a good idea and those are hard to come by.
On one of our globe mixers, it has a bolt on the backside what has a magnet in it so that when the bowl gets raised to mix, the machine has a way of confirming it’s in the right place.
That bolt got lost a while ago so I drilled a hole in a bolt and glued a magnet in it which then got lost yesterday, the magnet came out.
So today I had the idea of seeing if I could print a new bolt with a pocket in it for the magnet and then pause the print at the right time, set the magnet in it and let it continue so that it encases the magnet.
It worked, printed it out of nylon 12 which has a heat deflection temp of 120*C and is food safe and it’s semi transparent so you can see the magnet in there.
Pretty cool.
I tried taking some pictures of it but it’s hard to see since it’s a fairly small bolt.
Then it hit me that I Could probably do the same with some of the more expensive reed switches on various machines, probably end up better than ceramic casing with a reed switch epoxied into it which is what the OEM one is.
Buy the reed switch and then design it into the object and then print it, pause it, put the reed switch into the print and let it continue, sealing it up.
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12 Replies
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Very interesting idea. But one would have to know what the max temp of the reed switch will withstand. And the melt temp of your filament. Not all reed switches are made the same way or with the same insulation and internal mounting parts. . Some are a real low temp plastic inside and sealed with basically a glue gun. And there are a lot of different temp hot glues out there.
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Very true, it would definetley be a bit of test working but I think it could be done.
I think we would get the glass encased ones, that would probably work.
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This is so interesting! Is this your first time 3D printing a part you needed for a repair? Or have you been playing around with the capabilities a 3D printer allows for?
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Hey Mckenzie,
No not the first time, I’ve been printing for about 3 weeks now but been working in 3D for about a year or so.
I have printed a couple of parts already which went into machines, it’s a bit of a learning process since it seems like it very, very recently moved into actual real end use application so it’s limited as to what people have successfully done already.
I tried making a gear for a water softener, the main timing gear out of PETG and the teeth just didn’t survive so I was going to try Nylon and see.
This whole shabang started with me trying to make my own belt pegs for the dishwasher we have in house and it just kind of grew from there.
I’m currently working on the reed switch, got a switch and I’m trying to print the body of the part but it keeps popping off the bed but I’ll let you guys know how it works out, looks like it’ll work though.
Spoke to the manufactuer of the relay these reed switches power, said I could have 10 of these reed switches on it before hitting my 1A limit on the coil of the relay and there’s only 6 or 7 so on paper, it should work, in real life, we’ll see.
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As long as the Guass level at the reed switch is the same , you’ll be fine. But if the thickness of the plastic over the magnet is thicker, it will be lower and may need a more powerfull magnet.
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Very true, I tested it with a “template” print to get the layout of the reed switch and wiring properly figured before printing the complete model and it seems to work pretty good with a small magnet, the magnet on the machine is much bigger so I think it’ll work fine.
Only time will tell, if only this Nylon would stop warping and popping off the bed.
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I used to repair a lot of printing equipment. All the access panels and doors had safety switches on them. On one Mueller-Martini signature binder there was 18 of them Constant calls to figure out which one was off. I always had a clip on magnet with me to be able to jog the machine with a door open. But the operator would remove a reed and place a magnet from the door over it to defeat the safety. Not a good thing because they would never replace it. And if they did, not in the right position. I eventually installed a key switch to bypass the safety circuit for testing, but kept close control of the key. Made it much faster test and troubleshoot.
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Smart. that’s a good way to do that.
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Every call was about $300and I am a hour away from them. The older machines had micro-switches on the covers. Vibration was always a problem and the operators would tape them. In the late nineties they stated using reed switches and logic control. Along with a lot of proximity sensors.
To call a factory tech out for the printing industry, they had to come from NJ about 3.5 hours away at a rate of $250 per hour. And they are paid door to door. Made for a good relationship for me. Your looking at a field where a circuit board cost upwards of $12,000 exchange and ammonia is used for aqueous coating cleaning. Ammonia and copper do not get along well. A spill on a deck board would migrate down into a control box. Eating up 50 and 25 pin ribbon connectors. I had to buy a ribbon cable crimper and they aren’t cheap. But I could repair a board and replace the sockets for less than a grand. I’ve seen 6 color presses that have over 20 auxiliary boards. Each head had 50 servo motors for ink adjustment and two for cylinder adjustment. There is enough wire in one press to go to the moon and back. The schematics that comes with a press is a book 3 inches thick with some fold out pages. You always have to have a handful of book marks to jump around and follow a circuit. I do miss the mental challenges of it.
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Wow, that sounds like quite something.
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Here we go, the finished part with the reed switch encased inside, and it works on the bench 😀
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Here is the bolt with the magnet, in one of the shots you can see the magnet since the nylon is slightly see-through.
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