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So at present we are getting a maximum of 14 pieces per hour. Mostly limited to the slow speed of the extrusion machine at 3.1 kilos per hour. I will be speeding up the extrusion machine RPM and hopefully get the production level up more.
210 gram parts (with flashing attached) take about 1 min to cool enough to remove from the mold. However the parts could be in the mold longer.
Temperature was reduced to 200c last stage and first stage up to 195c. I only have 2 stages on heat on my machine, and the barrel has been extended an additional 100 mm past the end of the screw to give it more melt time and to dump more heat into the plastic before it comes out.
My extrusion machine appears to be running too slow. Based on calculations from a engineer who buuilds these things for a living, he told me that a 1 meter screw with 25mm diameter he runs up to 600rpm. He said that since half the length of the v3 Precious plastic design, I should look at 300 rpm max speed.
The heated pot design needs to be modified. Probably something with a pizza oven sort of tray to remove the slug, and re-use the turbo cooker heater top in a new box. On the priority list it is a bit low.
New extrusion machine is under construction as budget and time allow. Frame was mig welded up yesterday partially.
Extrusion machine barrel is up in size from the PP design on the next unit. Starting out with 1.75 inch round bar stock 24 inches long, turning down to 42mm OD and drilling out the inside to 1 inch ID so that gives a 0.4mm clearance on the screw. Also drilling and tapping the barrel to directly screw the thermocouple into the barrel. this gives me a 9.5mm thick wall on the barrel to work with as the portions where there is no heater band will remain the original 44mm 1.75 inch size.
The screw is custom made with a 1 inch shaft and key way. To better work with chain flex couplings.
The setup is strong enough that if the machine would be started cold the belt would slip before the shaft would break.
The new pneumatic bag jack powered molder and molds is on order in Laser along with more high speed shredder parts.
the scissor jacks, I just do not see them as useful.
Have built several machines for compression molding and broke 3 brand new jacks already.
As power for a injection molder yes, fine, but for the compression mold, not even close.
video of the output and you prob should slow it down a bit the blades. standard high speed shredders are running at 500 rpm.
My difficulties involve workers actually showing up to work, pushing brooms, and simple assembly of all the parts I had made. Welding, and machining items is beyond the ability for most of my applicants. Pay rate is irrelevant. I have paid handsomely, and poorly and I have had the same results.
I recently had my son join the team. He just finished his board for aeronautical engineering and is learning things to take over a lot of the day to day operations. However, he is also frustrated at the difficulty of getting even simple housekeeping tasks performed by the people he supervises.
It is a universal issue in the Philippines and one of the primary reasons why the country is mired in poverty. My Filipino friends who own businesses have said the same things.
With Precious Plastic, we are promoting to those willing, but as in all things, you can lead a horse to water, but you can not make him drink. Those who want to improve their life will, and those who won’t, will not.
The thesis project machines usually end up becoming the property of the school. It does not really seem right, but that is the Philippine custom.
those units in the youtube videos are a big step backwards from the existing machine development.
Any chance you could release the linear guide as a 3D printable STL? Really desperate here to build a CNC router. The MPCNC design is not sturdy enough in my opinion. I built a couple and lots of flex issues.
there was a South African guy using a car jack to open and close a mold for a kickstarter that was stillborn..
hydraulic is too expensive, although i am looking at a hand cranked unit and a timer to run the machine and control the amount injected.
This unit below is 106USD.
It runs a small 12v pump. Replace the pump with a SSR (solid state relay) and you got a effective way of metering the amount dispensed.
Over here in the Philippines we have been working in the mad scientist lab to make large numbers of plastic sheets.
We finally achieved success today.
One issue was warping.
Second issue was we was breaking car jacks making sheets
third issue was our sheets were not even thickness.
So We came up with this machine.
We melted in the extrusion machine into a turbo cooker (to keep warm while the plastic acumulated)
We then pressed with 3 ton jack with a press that was cold. We used fans on the mold to rapidly cool the plastic under pressure.
Results were a textured plastic sheet.
We are still working on surface finish, however we find that galvanized steel is virtually non stick to molten plastic.
We need to acquire larger sheets of galvanized steel to test out with larger shots, however in small shots, we had glossy plastic sheet finish.
if one had a proper enclosure for the spinning blades, much like the high speed shredders do…
I might be able to help. I have containers of things going to the US from here now.
re: the heat pot, I just used a stainless steel turbo cooker, drilled a hole in the side to pipe the hot plastic thru and used the existing controller. I also put a silicone lined bowl inside to catch the plastic and transfer it.
I chose the air bag jack because the air over hydraulic press are too slow. the plastic can cool before it gets formed. Also those jacks are very expensive locally. No reason for it, just local sellers mark them up a lot. Island economy and all.
might I suggest something called a chain flex coupler to connect your motor to the gearbox?
I attached a photo. These are the yellow parts of the shafting. cost locally was around 14usd each.
I have now also successfully used belt and pulleys to reduce the speeds.
My current shop frankenstein monster extrusion machine uses a 2hp motor with 4 pulleys and 2 belts to reduce the speed. I got the idea after seeing a commercial production type extrusion machine locally that used 1hp and the same method. the frame was welded angle bar.
Other donor frames and machines you could investigate is modding a wood lathe to power your extrusion machine, or turning a drill press sideways to run the machine.
For joining the parts you can check out plastic welding.
here is a example, but there are lots of others out there.
I modded a large soldering iron to weld plastic and used a dedicated plastic welding machine
in the video they show using a mesh to join parts. I used drywall fiberglass joint mesh successfully in the same technique. Avail in big rolls at your hardware.
Updates on my research here.
We broke several car jacks.
Abandoning the screw type car jack for now.
Purchased a 3 ton airbag jack to get more pressure.
1750 kg rated car jack was not enough.
Using the c channel frame as the linear guide to keep the press straight.
Results by mid November at latest. Lots of projects in progress here.
the pipe I have is 33mm OD so in order to fit the heater bands I bored out some female-female couplers as sleeves.
However it occurs to me that a easier method is to use short sections of plumbing nipples, couplers and a tee to make a no machining extrusion barrel.
Even though I have access to a lathe, sometimes the simplicity of putting the thing together from ready made stainless parts is easier.
Have run maybe 10 kilos thru the machine since it has been done.
The extrusion screw and shafting backed out of the barrel under pressure once and jammed the pulley. i may have to put some spacers on the thing to make it work right.
the washing machine experiment is a success. I filled the machine with aprox 7 kilos of bottle caps, added in a bit of bleach and ran the machine.
It came out nice. With the spin cycle there was not much water left and it dried fast. I then shredded it.
The washed plastic comes out much better than the unwashed from the extruder. no pops, steam, or smoke unlike the dirty plastic that has a lot of contamination.
It also smells better.
Locally I found new washing machines for 80usd without an agitator or spin basket. there are separate laundry spin baskets for sale locally that are fairly low cost.
So results are in with using the pipe tee for the extrusion input.
unequivocally YES IT IS WAY BETTER.
I was able to feed even the slightly larger pieces without problem.
the belt and pulley drive reduction still needs some tweaks. I did not use strong enough angle bar and part of the machine literally twisted itself.
Replaced parts with 1/4 inch x2 inch angle bar. Will see later this afternoon.
Also had a problem with the axles moving in the bearing blocks. Set screws were not enough to hold. So I will weld in some stoppers like I use on the shredder.
Otherwise, so far so good.
Also prob should add in more heaters, 4 is not even close to being enough.
Going back to the belt and pulley speed reduction instead of a gearbox.
Sheet metal frame, laser cut and CNC bent.
What appears to be bearings on the barrell, will be modded bearing holders.
Since these cheap bearings only cost a couple dollars, they are simpler to punch out the bearing and turn a holder on the lathe.
Easier alignment, lower cost. More professional looking than the present system
Looks interesting but I can not justify the price. There is the Spanish guy who has a extruder that does the same thing for a couple hundred euro, and printer costs have fallen so far now days.
With the shipping cost it is more than buying a new lathe and 6090 cnc router combined.
v3 is apparently larger,
However v2 step file is in the download pack, and the axle layout drawing is for a smaller v2 shredder as well
DWG is the format that my laser provider takes. Not a scaling issue, the step file was never updated in the download pack to v3
v3 CAD models are not in the current download pack. Just downloaded it again a few min ago.
the step files? Or the overview? so you are saying you reduced the size?
Because I downloaded the new pack recently and it still had the same files.
Can someone post the bigger step file model?
I have based all my designs around the larger machine as shown in the overview.
It is at least $150usd that will not go towards the R&D of my new combo compression mold/injection mold machine or a week salary for my
Whomever did the download pack, exported updated files for laser layout, but failed to export and update the solid CAD files.
Now i am sitting on a big pile of expensive scrap
Got a new sheet press running here in the shop.
Based on a bearing press.
I did see bearing presses for sale locally, but they were not that wide unless I went up to 10 tons and then the costs skyrocketed to 1000USD vs 300usd for 3 tons.
I used a car jack on mine.
Video here. https://web.facebook.com/preciousplasticphils/videos/2434277790125073/
1 ton per square foot or roughly every 300mm square pressure for HDPE.
I used 3/4 inch Phenolic plywood for the molds.
the plywood worked well except that it will needing more support on the top and bottom during the initial pressing. It warps at 1 ton as it was only supported from 2 sides. I have some 12mm MS plate that I will cut up to fit in the frame maybe this week.
I used a 50usd turbo cooker to melt the plastic in a teflon baking pan. the molten plastic will stick to teflon. It also stuck to a silicone baking pan, however It does not stick to a silicone spatula. Probably the grade of silicone. I prepared a pan with high temp RTV silicone gasket material yesterday. It has not cured fully yet. Possibly the tube I got was old. I will try it this afternoon and see.
If one is to do production, they would need at least 5 turbo cookers to make it worth while. Also insulating the turbo cooker so save on electric usage.
This method would have a much lower initial investment than using a extrusion machine, but over the long time, possibly a higher operating cost. Much would depend on if you insulated the turbo cooker (rated 1200 watts)
the turbo cooker has a fan which makes the plastic heat much faster than ordinary convection ovens.
Overall I would call the experiment a success.
Just reporting back on my development here.
After sharpening the v3 blade teeth to a sharp chisel point, and the 1.25 inch hex shafting with 25mm bearing. Upping the power to 5hp.
I am getting 50 kilos of bottle caps shredded on the existing design. However this is without a screen. I have to feed the material thru a second time to cross cut the material. It still does not like pet bottles much without crushing first. The blades wont grab it easily.
My double size shredder on the other hand grabs pet bottles nicely. Same 5hp motor. That machine has been running 4-8 hours per day for 2 months now at a plastic foam factory.
My other clients who shred mostly sachet do not get 50kg per hour. Mostly due to the bulky nature of the plastic. They feed the hopper as fast as they can with big handfulls of material. It digests plastic bags nice too.
So far jams result in the belt spinning not the motor stopping. On 2 latest machines, the belt is very tight and no jams despite over feeding it.
The use of a 63 amp transfer switch to reverse the motor has made life easier.
Initial supplier ripped me off with a german switch that cost 90usd. I since found indentical China switch for 15usd that i imported.
there is no GPL license! This whole thread is masturbatory at this point discussing something that does not exist! See the terms under which it was released. (screams in frustration)
@sharma-sagar need I refer you back to the terms and conditions also?
Originally we planned to write one of those long terms and conditions things here. Yep, super boring to read and write. So we made the short version: Everything is free for whatever use (commercial or personal). We would appreciate it if you mentioned our name somewhere though. Oh, and you can’t sue us if something goes wrong. Be careful!
As far as I am concerned, further discussion on this is a waste of time.