Forum Replies Created
@occupypp , Thanks, now I need to find a cryocooler on ebay…great. I wonder if he could do as well just liquefying dry air instead of doing the N2 separation, not that much warmer.
Yeah, unfortunately unless that feeder has a mechanical finger that can open a can of the good stuff, it has been judged inadequate in our house….cat eats better than I do.
Stefan’s workshop looks nothing like mine…hmmmm…
@ppme , since you have some great designs for combined pp machines, perhaps you could add one of these as an attachment.
As @ppme said, look in the machine section of the bazar on the precious plastic site. There are machines offered in various stages of completeness.
Originally I was hoping that when the V4 team had rented the professional machine, they could do a side by side measurement using the low cost sensor, mainly for information. I don’t think you can certify the air safe with one of these unless you do some serious lab work. Too much is unknown.
@ppme , yeah, it is not clear what the path forward is for the forum. There should to be someplace for the DIY recycling efforts to discuss issues and store solutions.
I think for the global save the planet from plastic efforts, they are migrating towards more ambitious efforts that are planning on collaboration with industry to affect change. This announcement https://www.minderoo.com.au/minderoo-foundation/news/global-industry-initiative-launched-to-end-plastic-pollution/ is a good example of big money and industry collaboration. There is still a place for a small solution to a local problem, and education, but the heavy lifting will be done at the industry collaboration level.
If the forum is meant to fade away, perhaps if it shifts to a different host just to maintain the basic function of technical Q and A and posting successes (and fails).
I think it is easiest to buy the SSR in a low cost bundle with the PID and thermocouple. They are available on amazon, ebay, or from China. An example here. https://www.banggood.com/search/1060462.html
If you are buying them individually, just make sure the PID is providing the control signal the SSR needs (like the ones in your pictures). Some PID’s provide a relay switch rather than a low voltage signal.
For the band heaters, just make sure they are 110V, have the diameter to match your tube, 300w is typical
I would go with the gear puller or a DIY equivalent that pulls on the hub while pushing on the shaft. Might be worth taking it to a local mechanic and they can probably pull it in 5 min. You can make something equivalent with a stout steel bar (or square tube), A hole near each end that you bolt (with a gap) to the hub and a hole in the center for something like a 10 mm bolt. You put a nut between the bar and the shaft, then as you screw a bolt through the nut (holding the nut), it should push on the end of the shaft while the nut pulls the bar (and the hub) off of the shaft.
Of course you could go brute force and carefully slice the hub lengthwise with an angle grinder with a couple of cut off wheels.
A mechanic may have an idea how to keep the bearing in the housing. I would probably just carefully glue it.
yeah, if it was mine, I would cut that black material off to see what is underneath. In the picture it almost looks like there are some threads on the shaft with maybe a lock ring?
What is that black, looks like heat shrink plastic, sleeve around the wider part of the shaft end. If that is plastic, I would cut it off to see if there is a retaining ring of some kind under it.
Can you take a picture of the end of the spool? Also can you push the shaft and bearing back in place? Does it rotate without wobble then?
Some experiments on dealing with wrappers here: https://davehakkens.nl/community/forums/topic/soft-plastic-recycling-research-and-feasibility/
I looked at the Drill press designs before I built the desktop machine in the other thread. The things that influenced me were the stroke volume and force I could apply. Even with the Arbor press design, I started with roughly a 30CC stroke volume. This worked fine but was very limiting on what you can make (you don’t get the full stroke volume into the part.) I then modified the volume and got 45 cc. This was better but still very limiting, especially since you want to have margin to minimize voids.
I then built a new hot end that gives me about 200 cc stroke volume. I can get about a 140-150 CC part out of this in HDPE. For me this is a usable volume. To get the 200 CC stroke volume on a desktop machine where vertical stroke becomes a constraint, I increased the diameter to 41 mm. This now requires significant force to achieve good injection pressure. I replaced the arbor press bar with one that is about 600 mm and I’m pretty sure I am applying more than the 1 ton rating of the press at times.
My floor standing drill press also has a limited stroke length and I believe significantly lower press rating. If I had used it, I would be limited to the much smaller volumes that I started with.
Before you go down the drill press route, I would recommend going through some of the volume and pressure sizing calculations and make sure it is worth it. I built my machine for about $100US. If I added a shop press frame (instead of the scrap wood) it would probably double.
@ppme , I always wondered if it would make business sense for you to make a version of your rack and gear that would bolt to the top of a shop frame and just sell/ship the rack/gear, letting the user source the rest of the parts which are relatively off the shelf or shop tool makes.
Actually, something like this may be a little stronger https://alexnld.com/product/4pcs-201-stainless-steel-spring-toggle-latch-catch-hasp-clamp-clip-duck-billed-buckles/ . Looks like it should be in the cabinet hardware section of the store.
To find stuff I don’t remember the name of I usually guess and google images. I either find it or get totally distracted with some other cool item.
Congratulations, sounds like a great event response.
With a second small shop frame you could add an arbor press based injection machine. DIY: https://davehakkens.nl/community/forums/topic/portable-desktop-injection-machine/page/3/ or something like this ready to go https://bazar.preciousplastic.com/en/listings/770058-arbor-injection-press-elena-catalonia
“something which doesn’t involve things like a nut”
Well, a bright orange pair of Vise Grips? https://www.amazon.com/Grip-Curved-Locking-Pliers-GR11105/dp/B008U4M0LU
If you are going to slot the top hole, then a stud (maybe a captive one that can pivot) and an orange knob might be easiest. You won’t have to unscrew the knob very far.
Looks like @patrick-bonsen used a similar configuration, perhaps he can comment on getting the spool off. Otherwise, perhaps you can borrow a gear puller or make an equivalent with a bar with a tapped hole on the center that you can then clamp onto the flange of the spool. A little heat on the spool core may help as well.
Yes, the first few parts off of the machine would be some signs and plaques for the wife’s hobby….I know how this works.
The MPCNC design is intriguing and fits well into my interest in the build itself.
I’m still interested in exploring cheaper/softer materials for limited use custom molds.
Thanks, the TipBlitz is great. The CNC is too pretty for my garage.
I have been thinking of making one of the MPCNC routers.
Good luck. While you are getting rid of the bubbles, if your team comes up with a repeatable way to determine internal void volume (perhaps just a careful density measurement) that would be a great step.
One question is how the strength changes with repeated recycling.
Your data will be of interest to the community, hope you can post the methods and results.
Those are great results.
I used an arbor press to provide the injection force in my DIY configuration. It works very well. https://davehakkens.nl/community/forums/topic/portable-desktop-injection-machine/page/3/
Thanks for posting, looking forward to how your improvements work out.
Have you seen this thread https://davehakkens.nl/community/forums/topic/polystyrene-transparency/ , especially the post by @imuh ? The image he posted is a lot closer to bubble free, perhaps he can comment on the process details.
The problem with concrete is that it is not dense compared to steel. The wheel in your second link is interesting in that filling the spoke area provides a lot of volume (and weight). If I was going to do that, I might add some wire mesh for a little bit mode reinforcement in case you drop the wheel during handling. You can also combine it with the metal weights on the perimeter or use a mold frame to make it bigger or thicker. The formulas above let you compare that case with the metal options. There isn’t enough volume in a tire to make filling it with concrete worthwhile, I don’t think (maybe the fat tire or motorcycle wheel).
To place the individual weights on the rim, the inertia formula does not care but you would want to balance it just for smoothness. How you attach them to the rim depends on shape of your weights. You could bolt them radially by drilling holes like your valve stem. You can also attach them to the side of the rim.
If you have access to scrap lead, you could make yourself a mold and cast weight segments that fit the rim.
I think any approach that puts on sufficient weight, is reasonably balanced, and does not fly apart should work.
Looks like a great experiment, good luck.
It would help if you described your process design. Is it limited to industrial sourced material?
I love the results Vanplestik are getting but I didn’t think they were using filament. I thought they used flakes and beads directly.