Forum Replies Created
I’ve been thinking about the saw blades of death approach. Since it will be taking very small bites, the spacers between the blades probably want to be almost full diameter to support the blade. I like the threaded compression mount you show.
For the thermocouples, their tips should be pressed against the tube but not the heater. Take a picture of one of them.
I think since the problem is slow warm-up, Most of that time the PID should be full on so I suspect you have 220V rated heaters and the one near the tip just does not have enough power at 110V to heat that part of the tube and maybe the aluminum frame fast enough.
I think you said you tried swapping the heaters and PID’s and it did not change.
If it is just a slow warm up, maybe you just live with it or if it is the wrong heater, You can get a 110V heater for the nozzle for not too much money on ebay. Too bad the builder isn’t helping you here.
When he comes over, I’m sure he will do it anyway, but ask him to check that all that metal framework is properly grounded.
Does that aluminum support plate get very hot? if it is in good contact with the bottom heater, you may be loosing some heat there. If you have a multimeter you could check the resistance of the heaters. Do you have 110V in Panama? If those are 220V heaters then you are only getting 1/4 of the rated power.
Sorry to hear about the builder not supporting you.
From the photos, It is hard to tell how the thermocouples are mounted. The tips should be pressed against the tube but not the heater so it is not measuring the heater temperature. Other than taking long to warm up, do both controllers reach temperature and stabilize?
Do you have a picture of your PID/SSR/TC/heater set-up? I use the really cheap Berme units that often come in a PID/SSR/Thermocouple kit and they work fine. From the specs, it looks like the Inkbird is maybe a step up from that.
Can you take a picture of how the heaters and thermocouples are mounted?
You definitely need to consider the fumes from a worker safety aspect, but in terms of external pollution, hopefully the quantities are small enough to be exempt. Maybe contact a small injection molding company and see what they had to do.
If you look in the Bazar, there are several US based builders that may be able to help you.
Yeah, PP is more brittle. I would try PE before modifying the mold.
Yeah, impatient me.
I am curious if I can adapt any of the cutter geometry to the low speed garden chipper I acquired.
OK, I’ll go watch Colin Fruze videos in the meantime.
@ppolice , do you have some pictures or video of the grinder in action?
That looks great. Is there an advantage to the air bladder compared to the air driven hydraulic jack? https://www.harborfreight.com/20-ton-air-over-hydraulic-jack-95553.html
Can you comment on the cook pot? I’ve been considering one for either melting or pre-heating for the injection machine. Did you add a better temp sensor and controller or just used what it came with?
Thanks for the update.
Yes, great video. Every summer I enjoy the inevitable stories where someone discovers that the giant inflatable swan is really a good sailboat and ends up several miles offshore…at least they are easy to spot.
@anomaly , The shredder doesn’t recycle anything, it is just an intermediate step. It is also one of the more difficult/expensive things to build. You should check out what Precious Plastic Latvia https://davehakkens.nl/community/forums/topic/precious-plastic-latvia/ have been doing. on their youtube channel they have a great video of the bicycle drive shredder in action.
If you are new to plastic recycling, take a look in the Bazar at what people are producing. For the press machine, the molds if any, are relatively simple. For the injection machine the molds can be more intricate (and expensive). The extrusion machine needs small chips (i.e. shredded). The other machines can accept larger, hand cut pieces.
Depending on what you think you want to produce as a final product, and your resources, then pick the machines to start with.
For a teaching environment, plastic fumes need to be addressed. While things like HDPE are more benign, there are still fumes. There is some info here https://davehakkens.nl/community/forums/topic/v4-fume-extraction-4/ . If you can do the hot processes outdoors, that would be a great start. You might contact the team at Monash university to see what regulations they had to deal with. I would guess you will need to go through some general safety reviews in implementing you project.
Unfortunately, while there have been a number of people with questions about starting education programs, they often don’t come back to the forum to share their experience.
Great idea, and good luck
I have not done phone molds but, which plastic are you using? LDPE or HDPE should give you a bit more flexibility.
@anomaly , For human powered shredder, there are several threads, including this one https://davehakkens.nl/community/forums/topic/bicycle-shredder-costs-work-in-progress . Note the great video by @thetank at the end.
Just curious, have you built one of the other machines? The shredder is not always needed right away.
Nice, well packaged for demonstrations. I definitely need to add some flashing lights to my injection machine. What is the stroke volume of the machine?
@thetank The shredder looks great. Have you tried different gearing to slow the shredder down and maybe a flywheel?
I think you just need to change the marketing. Here in the US, there is no shortage of people willing to pay good money for the pain and exhaustion of a stationary bike in a health club spin class. I think if you add some web connectivity, a new fad of competitive plastic shredding will be sure to follow.
Sounds like a great program. The hand-cranked shredder should benefit their athletic program as well.
Hopefully their makerspace is set up with some fume management for the injection machine.
Yes, you definitely want to research this and be overly cautious.
Some info here, https://davehakkens.nl/community/forums/topic/v4-fume-extraction-4/
Also search the forum for other threads. In general PP has not addressed this issue conclusively.
I don’t know about a .csv of the data but the map features/filters become usable when you click on the “add yourself to the map” button.
How well and where the thermocouple is mounted is an important factor in how well the PID works. I’m using the cheapest REX-C100 clones that don’t have tunable PID and they generally go straight to temperature. It helps that my tube is aluminum and the thermocouple has its own clamping block.
Those may be OK for initial compacting the plastic as you load the pipes but the final compression needs a lot more than hand pressure. I would plan on at least large C-clamps pressing on some round stock, with frequent tightening as the material contracts. If you have access to a shop press that is better.
Well, if you have an extra half hour for classic metal working from scratch. The two Ford Hallam videos have been out a while but are eye candy I could use as a screen saver every day.
Of course you can use his techniques to make molds….who needs CNC.
Great work, as a back-up if the long extrusion proves difficult, Maybe try some heat welded lap joints to create a longer beam. I would probably include a bolt just for extra security.