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You might try just the self adhesive pin backs like these. https://www.hobbylobby.com/Beads-Jewelry/Jewelry-Findings/Apparel-Accessory/Self-Adhesive-Pin-Backs—37mm/p/105659
That’s what I used on the large (~70mm) buttons I made last year. https://i0.wp.com/davehakkens.nl/wp-content/uploads/2019/07/Buttons-2-s.jpg?ssl=1 There is one hanging over my computer and it has not come off.
Otherwise, there have been posts on heat welding HDPE that might be applicable.
We are trying to help you but just telling us your system does not heat the tube above 120C is not enough. Pictures, wiring diagrams, troubleshooting results, brand of the PID (some have no parameter adjustments but work OK), and any other information you have.
Also note a 400V 300W heater operating at 230V only puts out 100W
A lot of confusion here. Based on what you said, your PID is the is the relay type (type M). It does not provide DC output but just acts like a switch. You connect it between your DC power supply and the SSR DC input connection. You can connect it into either the positive or negative side your choice. If you pick the positive side. As was described earlier, you connect DC power supply positive to #4 on PID then connect # 5 to positive on SSR. Connect negative on SSR directly to negative on DC power supply. When PV is below SV, the PID output light will be on and the internal switch between #4 and #5 will be closed and the SSR light will be on and power will go to your heater on the 220 side. If that does not happen I can’t help you further without a picture of your wiring.
Sorry without pictures or model information, I’ve run out of suggestions. If the SSR is not connected directly to your power supply and the SSR light stays on when the PID output light is off, check that you are connected to the correct output terminals. Otherwise check that the PID by itself is working properly with a continuity test on the output.
I prefer to answer in the forum in case others have similar questions.
I am assuming your PID looks something like the image below. In that example connections 4 and 5 are the PID output for the SSR (relay in your case). Those two connections are two sides of a switch. The positive side of your power DC supply connects directly number 4. Then a wire from number 5 connects to the positive on your SSR. The positive from your power supply does not connect directly to the SSR (otherwise it will always stay on). As stated above the negative from the power supply connects to the negative of the SSR.
Just to confirm. The positive from your 12 power supply goes to the back of the PID to the relay connection (4?) and then connection 5 is connected to the positive on the SSR. The negative from the power supply is connected directly to the negative on the SSR.
With a voltmeter you can confirm that the input to the SSR turns on and off with the green light on the PID.
“Yes when I set the PV value higher than the SV value the green light went off”
When you are changing the values on the PID you are changing the Set Value (SV) the PV should be what the thermocouple measures.
You can check the PID with just local heat (fingers, match, etc.) on the thermocouple.
SV greater than PV, output light on and DC voltage at SSR input
Warm the thermocouple to PV greater than SV, output light off and no DV voltage at SSR input.
Placing the thermocouple on or under the heating band can cause problems. the thermocouple needs to measure the temperature of the tube you are heating not just the band. See some of the other threads for more discussion.
One side of the DC circuit passes through the PID before it gets to the SSR. The PID acts as the switch for the DC circuit.
It is hard to help trouble shoot without a picture or schematic. Is the heater and thermocouple installed on a tube? How are they installed? Are you using a type K thermocouple? When you first turn on the PID does the PV show a correct temperature for the room?
Without power to the heater, if you set the SV below the PV, is the output light off and the PID output switch measures open (or with your DC power supply there is no voltage at the SSR input) and the SSR output is off. When you increase the SV above PV, the output light comes on and the PID switch closes, with your DC supply, the SSR input has voltage and the SSR output is ON. Does all that happen?
Take a look at your instructions. Does the M in the model number mean relay type? I think your SSR is looking for a DC voltage to turn it on but that model provides just a relay switch but not a voltage. If you can exchange it, a type V may be what you need. I you can’t exchange it, you may just need to add a low voltage DC source to operate the SSR through the switch in the PID.
I’m just guessing so post some pictures if you can.
Hey, Great Work!
You made a lot of progress in improving the safety, reliability, and effectiveness of the PP machines.
Yeah, the – what to make – and how to make it cost effectively (molds) is the next step to go beyond educational demonstrations.
I’m curious who your customers were (categorically) education/universities, government or NGO sponsored workspaces, or self sustaining workspaces.
Good luck going forward and thank you for all that you’ve done.
Nice design. I think if you were to reduce it to basic functionality the cost would be pretty low. All the 3D prints and bearings are nice but could be done in other ways. Printing the timing pulleys and the grinder mount is convenient. Here the grinders can be bought for $15. You can skip the chuck if you are willing to size the hole in the timing pulley to your part.
The Robodigg parts are nice, but if you need something local.
Do you really need super polish? Isn’t there always going to be shear within the plastic? Of course you could use polishing wheels on the grinder and use a router speed control (<$20) to slow down the grinder.
Interesting, I have SDS concrete bit that is waiting in the project cue.
It is hard to tell, but if the white wires are going to your load, it looks like you have going and returning to the same connection (1) on the PID, instead of what is shown in your second diagram.
If that is the common online PID bundle, with the BERM brand PID, I don’t think there are any PID parameters to adjust. But you don’t need to for this.
It is difficult to see your wiring in the photo. This discussion may help you.
If it is a smooth sphere, for a low cost mold you could try one of these, Carefully cut it in half and encase each half in something strong like mesh reinforced concrete and a steel box.
I’m not sure how you avoid bubbles or voids. I think the compression approach would do several flat melt/press/fold cycles and then compress in the mold. Probably depends on how efficient the process needs to be and how many you want to make.
If you are going to use an injection machine, there is a lot of pressure. Even if you encase the mold in something rigid, I’m not sure you can hold shape or detail.
Also, a 12 cm sphere is about 900 cc. That is a lot for an injection machine.
You might check with the local gardening people. Depending on what the local soil is like, it can be used as a soil additive. We just put ours into our compost bin. I’m sure the worms work faster when they hit the espresso grind.
The PP approach to mounting the TC to the tube may not be the most reliable. Take a look at my suggestion (April 21 post) in this thread and see if it makes sense.
Just to confirm, When you use the screw type temperature sensors (type K thermocouples) that came with the controller, you have them attached blue to 9 (-) and red to 10 (+). Also your controller model number has a K after the F, indicating it is for type K thermocouples. I can’t tell what your other temperature sensors are but if they are resistor type, they won’t work.
Interesting, Could you provide the steps. Are you using plaster and a bakeout oven?
Did you buy the temperature sensors with the temperature controllers as a kit? Does the temperature controller part number call out the type of sensor you are using? Take a picture of the sensors, the part number and your connection. Something is not matching up. If you are using thermocouples, are the tips undamaged?
Hopefully, since both are doing it, it should be easier to find the cause.
Yeah, I noticed the other day that the only activity was a spam post to a spam topic.
Agreed, there was some good discussion and excitement when this forum was active.
Looks great, what force does the cylinder produce?
I believe you. For general purpose, large area compression you need lots of force. The thought was for the relatively small, pyramid shaped mold that a 2 ton jack might work. 3 broken jacks say otherwise.
Those look really great. I really like your “engineered with what’s cost effective locally” approach to building your machines.
Would a motor (drill?) driven scissor jack work as a replacement for the log splitter?
Thanks for the update.
I am not personally involved in these efforts so I don’t have any direct information but here are a couple of links to get you started.
Sorry but if you search the forum, there have been several attempts at working with PET. The only successes I remember are the finely shredded PET used in direct 3D printers. The general observation appears to be that PET is both moisture and temperature profile sensitive and may be too difficult for simple DIY recycling.
@ha-ng I would set those 110V heaters aside. At 220V you would be pushing 4X the power through them. If they have not fried yet, they will. Before you wire everything up, I would check things individually. The PID controller should work just fine with just the thermocouple attached. The displayed PV temperature should look right and respond to holding the TC tip in you fingers. If you set the SV to 30 C, the output light should be on and you should have low DC voltage on the output terminals of the PID. When you hold the TC tip in your fingers, the PV should rise above 30C and the output light should come off and the output voltage turn off as well. If all that works, you can connect yous SSR’s and repeat the process. If you suspect the SSR’s I would check them separately using a DC source (battery?) to activate them.
The blocks I was talking about was for mounting the TC’s to the tube. I think the original PP approach for mounting the TC calls for removing the threaded mount on the TC and clamping under the edge of the heater. I didn’t like that approach. First, the TC bead in the tip can be fragile and second, I don’t want to measure the heater temperature, I want to control on the tube temperature. So in my implementation, I used a block with a threaded hole to mount the TC using the original threaded mount and press the tip of the TC against the tube, near the heaters. The picture below shows my build. It is a little different and uses an aluminum tube. For your application I would not bother screwing the block to the tube you can just clamp it with a hose clamp and install the TC through a hole in the hose clamp. You can even just use a nut for the block. At one point there was a picture on the forum where a really clever builder used the hose clamp approach. He welded the block to the hose clamp for a very professional look but that is not needed for DIY.
Also, there have been several threads recently troubleshooting injection machine builds and electronics.