hey,
there is a new hack by Colin Furze :
https://www.youtube.com/watch?v=E1dTwm8Lmpc
I ordered the parts and the material bill is around 800 Euro, still a good alternative to the yet clumsy v3 injection which are priced at ridiculously 700 – 1700 Euro in the bazar.
Anyways, I hope this one can be turned into a semi-automatic press. It won’t take much to make quick clamp system.
I would be happy about input, for now it looks all easy 
I wonder if an air driven hydraulic jack can be made to work since air is often already in the shop.
https://www.harborfreight.com/12-ton-air-hydraulic-bottle-jack-94487.html
or
https://www.harborfreight.com/20-ton-air-over-hydraulic-jack-95553.html
Though Colin’s approach of a central hydraulic pump powering a number of tools may have an analog in the shredder/heat press/extruder/injector setup.
Yes, always love watching Colin create stuff.
@s2019 I have more expertise into material sciences and welding, so hydraulics is quiet new to me. I worked on boiler building for a few years, so I know the pressure danger, pressure gauge and safety valve, even if in that case, I don’t really know where to place them. I’ll dive into that, there is probably a way to monitor hydraulic pressure or a way to relate air and hydraulic pressure.
I didn’t thought about a load cell, that is very smart, even if it might be very pricy as you said I guess.
@cgoflyn Yeah, the hydraulic based shop is just a thought exercise, I have not worked in that field. Browsing some of the supplier sites like (e.g. https://www.surpluscenter.com/Hydraulics/ ), it looks like hydraulic motors that provide low speed and high torque are not that expensive. The shredder and extruder both want that combination. For the press and injection machine, the rams/jacks are also reasonably priced. You do need a pump, but since everything except possibly the shredder is low duty cycle, the pump does not need to be sized for the combined use. For remote locations, the pump can be gas engine driven to reduce power requirements.
Interesting
@lagrenouille I have not used the air/hydraulic jacks or designed a system to use them so my thoughts on load monitoring are not based on direct experience.
The expensive way is to put an industrial load cell into the loadpath. Even surplus, these can run hundreds of dollars plus you need to configure a readout. If you have an electronics background you could attach a straingage in your loadpath and calibrate your system. You could calibrate your system by pushing on something predictable like a simply supported beam and measuring deflection. You could also build in some compliance in your system where you can measure deflection with an indicator and calibrate it as mentioned. Not sure if the air pressure can be used to control/monitor the hydraulic side. If your system has some way of accessing the hydraulic pressure, maybe through a pressure relief/release valve and you can T in a pressure gage and relief valve (like in the Colin video) without losing any safety function. All your fittings need to be hydraulic rated.
I don’t know your technical background but it may be worthwhile to get a hydraulics technician/engineer look at what you are doing as a double check.
Good luck
@s2019: ‘analog in the shredder/heat press/extruder/injector setup’, I cant get my head around all yet but i am definitively interested, one force source to power them all just like in old steam shops
Be careful putting these jacks on their side, they are designed to work upright and may not work at all in any other orientation, though you can get ones specifically designed to work horizontally.
I modified a standard one to work upside-down once, which involved adding a siphon tube and springs to keep the valves closed upside-down. It worked for a while and then broke, so I just flipped it right way round and made do.
To get an idea of how much pressing is needed I guess you could design the mold in such a way that it’s visible when the mold is full. Tiny holes in the mold that show the plastic has run through the mold for instance? But I guess then you still need to respond fast. Can you control the speed of the hydraulic press?
Or an adjustable end-switch that moves along with the press so that the hydraulic press turns off when you’ve injected a certain amount of plastic? One could then calculate in advance how much plastic is needed to fill the mold and work form that.
there you go. doesn’t look too hard to do
yes, i have the same concerns. a hydraulic is a pretty brute force usually and currently I don’t know better than fiddling around long enough to figure the pressure/way needed without to much destruction
if you look at Colin Furze’s video, you can see that he placed an extra valve in place, dealing exactly with this problem.
@s2019 I am currently building a new injection machine for myself, based on air driven hydraulic press ! I shall have all materials befor this week-end, the building should start friday evening.
I have a question, that you might have the aswer : I am afraid of the really high pressure that can be put in the mould, with no real control (you don’t really feel it once you inject the air). How would you control the pressure during injection ?
air driven hydraulic : yup, i saw such things too, powering a standard habor freight 20T press. problem seems to be the noise and deposit tank size. but even though, i want to give it a try
g
