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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.
There should be drawings and a bill of materials in the download kit. The important thing is what is available in your area. The inside one (piston) is usually a solid rod, though if you find a way to close off the end and the walls are thick enough so it does not bend, you could make a tube work. The outside tube and the band heaters you can find need to be consistent in size. As the instructions say, check the outside tube to make sure it is smooth (no weld seam). You could use aluminum if you have a good way to attach sturdy mounts.
The heater bands and controller/SSR/TC part of the system is probably a must buy, though you may have some heater equivalents. They are relatively cheap.
If you have a way to provide a low speed/high torque drive with your current equipment that is safe to operate, you may be able to save that part. If you search the forum, there are a lot of discussions on speed/torque/couplings.
Your band heaters are rated for 110V I don’t think they will survive 230V. I also would not run them for very long in the desk top configuration, there is no temperature feedback.
With the SV higher than the PV the output light (top left, second LED down?) on the PID should be on.
I would disconnect the heaters and measure the resistance. You may have burned them out. With them disconnected, I would disconnect the 230V from the SSR’s and check that they are switching properly.
As an aside, in your diagram, you have the SSR’s connected to line without a switch. I would run them through a switch just so you can safe the entire assembly.
How do you plan to mount the thermocouples to the tube and nozzle. People have had problems with the PP approach. Using a mounting block approach may be better.
Let’s say you got your hands on an industrial robot. You could raise your environmental karma by sorting plastic https://davehakkens.nl/community/forums/topic/sorting-plastic-with-robotics-v4/ or you can do this https://www.youtube.com/watch?v=_P4xiNx-hc4 (you can skip to 2:10)
If you need more pressure using the current levered design, @andyn made a clever change in his version where he could change the piston diameter without changing the tube. Of course, you trade injection volume for pressure but for small molds with narrow passages it may be an option.
It should just be the area of the piston face pushing on the plastic. In your case
I get 5.3e-4 sq meters and about 39.6 bar. I think to get to 45 bar, the PP guys eat more chocolate.
Sounds like a great project. Is there a link to a more detailed description?
I’m curious what is the predominant plastic type that will be processed and what will they be making?
Thanks for posting.
Well, if you are building a machine to the specifications on that page, it states that it has a leverage of 3. So if you are 70 Kg (about 700 N) and hang of the end of the bar, you will apply 2100 N of force on the piston. If you divide that by the area of the piston in sq. meters, you will get the pressure in Pascals.
If you take more accurate measurements of the machine you are building, you will get more precise estimates for your machine.
If you need more pressure, the rack and gear designs are an alternative.
They should be near the heaters they control but the sensor tips should be on the thing you are trying to control the temperature of, in this case the tube and maybe the nozzle. Take a look at my description in the Dec 14 post in this thread https://davehakkens.nl/community/forums/topic/injection-molding-what-am-i-doing-wrong/#post-151288 . If you follow that approach, I would dremel a shallow dimple for the thermocouple tip to press press against. The laser should work but may not be precise enough at this temperature. A BBQ probe sensor could work as well.
It is hard to tell from the photo, but it looks like the thermocouples are attached to the heater bands. The tube may be cooler. Do you have a way to measure the tube temperature independently to check?
There are several threads on this issue like this https://davehakkens.nl/community/forums/topic/v4-fume-extraction-4/ . Looks like the V4 efforts finally started to address safety in some of the designs and documentation https://preciousplastic.com/solutions/machines/overview.html .
If you have 3 machines going at once, I would make three fume hoods extracted by a common fan and ducting. Whether you filter the exit probably depends on your local situation
I guess, technically it isn’t single use plastic anymore. Now if we could set up a nuts-for-bags exchange program, the forest would get cleaned.
I don’t have an answer for you. 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.
You didn’t say what discipline you are studying, If possible, I would consult with a polymer chemist to get a recommended process cycle and control tolerances.
Do you know it is HDPE? The link you provided said polyester.
If it is only HDPE, that should work well.
Plastic yes. Used toilet seat….not so much.
Also if you see these guys coming……Take down your “zimmer frei” sign…just a suggestion.
That is a great summary, thank you
The spec table for the V4 sheet press shows 1.5 KW not 15 KW do you know which is correct?
I think the basic question is how much energy is consumed to heat up the machine and then make each sheet.
You may want to check the build documentation for the exact heater power ratings. I would guess the numbers specified are the total for the heaters. I have not seen a number for the actual energy used per sheet. You are heating up a lot of material other than the plastic so energy consumption will be significant, especially during the initial heat up. If you are talking about the large V4 sheet press, you may want to ask the question in the V4 portion of the forum or on the Discord channel to see if any of the PP people respond. Good luck
The page shows 2.8 KW for the basic and 1.5 KW for the pro, though it probably depends on your build and use.
You may want to put your question into the precious plastic portion of the forum (rather than the phonebloks)
Also, there is some information on the precious plastic site https://preciousplastic.com/solutions/machines/basic.html
Solar concentrators are always interesting and there are many designs. It would be nice if they posted some engineering and performance data for the lytefire system.