Arbor Press v14
This topic contains 15 replies, has 3 voices, and was last updated by Anonymous 2 months ago.
here the drawings and infos for a simple arbor press
difficulty for machinists : medium, 1-2 days
difficulty for beginners : high, 4 days
needs: CNC mill (aluminium), drill press (precise), metal saw (precise), lathe, and a good welder and the usual hand tools like angle grinder
material bill: 80 – 200 Euro, depends how efficient you can source it
– can be scaled to 45 cm by 25 – 28 mm diameter
– gearbox can be done more simple with 2 metal plates, without a CNC
– recommended class room machine, can be operated by kids higher than 1.30 m
– shipping size, 110 x 55 x 20 cm, 40 KG, 70 – 130 Euro within Europe.
I am adding more details (sources to parts, build steps from start to finish) on github the next days.
@pporg , Thank you. It is very generous of you to publish the details of your great design, given all the hours you put into it.
hey @s2019, I just copied/re-designed this from Taller Esferica, for easy re-production (kind of, its actually pretty lengthy and tedious to make one). They seem to have a different gearbox but i have no details til now. However, its a module 3 rack and pinion, with a spur gear of 22 teeth. I guess this can be optimized further but for now its quite easy to fill a mold with that.
If possible, measuring the torque or applied force that it takes to fill a typical mold may give some idea on how much the piston diameter could increase. A luggage scale might be sufficient to do this. It might be a path to significantly larger injection volumes than the V3 PP machine.
I have not seen the Taller Esferica machine, but yours is a pretty clean product.
thanks Stan 🙂
neat idea with the scale! I used a simple person weight last time, it reached the max.
that are the updates coming this weeks :
– one more spur gear to double force, with that I will close the gear box entirely as you already suggested, but also add grease plugs
– increase barrel size to 35 mm
– a higher/longer variant to use the full 50 cm of the rack = needs detachable feets to make it all fit to the shipping constraints. this gives about 45 cm by 35 mm diameter shot size.
– improve ergonomics & safety regarding filling the chamber. the plunger and barrel is pretty hot ..
– holes along the side bars, being able to heat insulation, so the entire inner space of the frame will be closed
– last not but least : supports for fume extraction
Gee, if you are measuring the torque in person-weight units, you might have to slip on an extension. I think the luggage scales max out at 50 Kg or so….well below my person-weight.
Looks like a great list of upgrades.
Great, clean details…. I also like the log splitter in the background….for dealing with those stubborn shampoo bottles???
Yeah, some polish and maybe put the sprue on the other side of the mold. I’m glad the machine doesn’t require person-weight magnitude force to do detail parts. Should work well in the school environment.
@pporg it looks quite good. Hope i will be able same or better results.
Surface of this case is caused maybe because CNC milling, or because of plastic used for the injection.
Do you know, what was the cost of the mold ?
@hugonator, mold cost: I don’t know, PP said once in a video around 7-800 Euro or so; could be less. a low budget machine will be busy 5 – 8 hours, a machine shop could make it for 500 though if you prepare all the CAM operations. A good CNC could do probably in 1-2 hours 🙂
hey there, I am still a little puzzled about the injection’s nozzle and adapter. currently we
1. make a M8 thread into the plunger, in hope this provides a way to put whatever on it but I think a simple M8 ACME thread will kick through the nozzle/adapter hardened left overs or just to keep it open …
2. the plunger gets a little inside bevel (clearance) with a relative sharp edge to helps ‘scratching’ plastic off the barrel, in theory
3. the nozzle/adapter is one piece, a M20 nut (mold input) can be still covered by a heatband; not well covered but ok, at least some heat; otherwise users can still machine a disc. we put it into the barrel with a press heat fit and the upper part gets also a 45 degree (??) slope to ease flow. the inner diameter is 12 mm, machined with a riemer and additional hardening.
we’re about to outsource the 3 parts soon (barrel, plunger, nozzle/adapter) so that’s a good time to still make adjustments or improvements, happy to have your input.
here’s one TIG brazed (that’s the one for you @hugonator);
I think giving those out to special vendors will be at the end cheaper; double/triple quality for the half of the price one can do in a home shop. it takes almost 3-4 hours to finish the whole set, plus there is realistic chance to get a close mechanism in there (heated too). best would be to have this also working for the extrusion; finally off-the shelf components for PP 😉
I’m not sure the M8 rod is needed. It will constrict the nozzle for the last few centimeters of stroke, also not sure what it does for the compaction process. I think using some plastic to purge the previous plastic may be unavoidable and is part of the heat-up process. I can’t think of a reason why beveling the end of the plunger and the top of the nozzle would be needed. Flat on flat with minimal dead space should work. Having provisions for attaching a temp sensor and a heater band as close to the nozzle as possible will hopefully provide the local control needed to keep the nozzle flowing.
Nice of you to include your special vendor in the photo. Ours also has a low hourly rate but has a short attention span and naps a lot…Severely affects the delivery schedule.
great, thank you again; I am often just trying to make the best possible. The bevel comes from applying cutting practices as you would do in creating a drill or lathe or mill cutter but I guess you’re right, flat on flat should do fine. The idea was as said to scratch off sticky left overs more easy. And the M8, yeah, I guess I will leave the tapped hole at least 🙂
The vendor in the picture is just like yours, never on time. Her specialty is falling from tables or sofas due to excitements about literally nothing but just seeing us around 🙂
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