Screwdriver
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These printed plastics are surprisingly strong in compression but in bending, especially for a finger brake, they'd snap unless you were practising origami.
Mind you, there's an idea...
- Thread starter BelgiqueB
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These printed plastics are surprisingly strong in compression but in bending, especially for a finger brake, they'd snap unless you were practising origami.
Mind you, there's an idea...
Not sure I follow. The finger brake is only under compression, there's no bending of the plastic.
Screwdriver
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My mistake then, the language around some of these mechanisms is relatively fluid. I assume a press brake pushes a blade (or finger?) into a die and a finger brake is more like a sheet bending mechanism, like a pan brake.
What is the difference between a press brake and a finger brake?
AndersK
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A finger brake is just like a regular brake but you can remove sections of the upper clamping part.
You fold the sheet by rolling the lower die upwards.
And yes, the fingers will take bending force, not just compression.
A press brake bend the sheet by pressing down the upper die into the lower V-shaped die. Usually you can remove sections of the upper die too.
You fold the sheet by rolling the lower die upwards.
And yes, the fingers will take bending force, not just compression.
A press brake bend the sheet by pressing down the upper die into the lower V-shaped die. Usually you can remove sections of the upper die too.
Screwdriver
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That's what I had assumed a finger break was. I don't think you could make one of those out of plastic...
Screwdriver
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Yes I am not suggesting you are wrong to call it that but I had always assumed <as above>.
The language is fluid, not sure if there is a right and wrong to it. I actually have a fair few sets of "fingers" for my flypress.
But I would still call that type of mechanism a press brake.
The language is fluid, not sure if there is a right and wrong to it. I actually have a fair few sets of "fingers" for my flypress.
But I would still call that type of mechanism a press brake.
But I would still call that type of mechanism a press brake.
With fingers :P
Screwdriver
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No I agree!
I've seen a few videos of people using plastic printed parts for a press brake. Quite keen to try that myself as even with quite a decent range of (imperial) brake tooling or "fingers" as you might call them 
, I often run into issues with box folding where I am in between sizes to fit the box iyswim.Very nice. What did you print it out of?
I'm thinking of printing a few lathe related items and using PLA not entirely sure how well it will stand up to the slideway oil.
Helder
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The main problem with 3D printed parts is adhesion between layers. That is generally the weakest part and will fail under tension/shear.
When you get a moment that causes shear along the layer lines that will fail relatively easily.
Like any anisotropic material you need to design with the "grain" in mind.
If it is loaded under pure compression you should get pretty decent strength.
Looking at the doc here they got 13600 PSI (~93 MPa) compressive out of 100% infill PLA. That's a little over a third of mild steel so not bad.
With the small surface area of the fingertips (assuming 1mm wide) you'd be able to apply about 90kg per cm length of break.
ABS at 7100 PSI did considerably worse under compression. Possibly because it is more brittle?
Screwdriver
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Printed this in PLA and it's as solid as a rock!
Heavy but lightweight for what it is. There will be a ton of info on which solvents dissolve which plastic but my guess is PLA will survive oils quite happily. Won't be so good with swarf tho, especially hot chips as they come off the lathe.
Really the only issue is very low temperature resistance. You probably wouldn't want to leave it in the window on a sunny day.
Heavy but lightweight for what it is. There will be a ton of info on which solvents dissolve which plastic but my guess is PLA will survive oils quite happily. Won't be so good with swarf tho, especially hot chips as they come off the lathe.
Really the only issue is very low temperature resistance. You probably wouldn't want to leave it in the window on a sunny day.
tflnemesis
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PETG is the best non-reactive plastic i print with, won't even react with acetone.
PLA can be annealed in the oven if you pack it in salt. The finer the grain, the better. You may even be able to use something other than salt, sand or talc maybe?
Anyway, this increases the strength drastically. There's a few youtube vids on it.
The layer adhesion problem can be improved on by using a larger nozzle. Typically you'd use a 0.4mm nozzle for most things and overextrude to a certain degree. I had a stab a printing with a 1.0mm nozzle with low layer heights. It seemed to go well (eventually). No idea of how well the layers were bonded though...
Anyway, this increases the strength drastically. There's a few youtube vids on it.
The layer adhesion problem can be improved on by using a larger nozzle. Typically you'd use a 0.4mm nozzle for most things and overextrude to a certain degree. I had a stab a printing with a 1.0mm nozzle with low layer heights. It seemed to go well (eventually). No idea of how well the layers were bonded though...
DAPPH
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Did you find you had to up the base board to 40 mm thick and slip a Formica topped shelf under the printer to ensure that slight movements don't cause the printer skeleton to twist ever so slightly & upset the bed levelling
My Prusa is fully enclosed with a slide across in a gully single sheet of Perspex as the front door ( sides , back , top & bottom made from new 20 mm construction ply glued & screwed .
I had to be modified to have a thicker easily cleanable base /floor so now sits on a 40 mm flat work top. Found out with a single 19 mm floor as the humidity changed so did the levelling . I glued & screwed on two more 19 mm construction ply bases with the grains running at 90 degrees to each other making 57 mm of base board then slipped a Formica encased cupboard shelf inside the cabinet , gluing & counter sink screwed it to the ply bases. I can even slide the printer around over the work top and nothing appears to have moved out of alignment .
Onoff
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Not had any bed levelling issues.
Have just ordered an IKEA LACK table to sit the printer enclosure on. It's what the enclosure was going to be made from but at the time, during lockdown, we could only get them in brown. Thus copied it using scrap wood to make a 550mm cube.
DAPPH
as dyslexik as I'm daft
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Using 19 ply for the sides & back was a lot cheaper than using perspex plus it's not source of static Got it cut to precise dimensions at a B&Q place that has one of the big wall mounted precision saw tables .
Having left it as natural wood colour it's well lit with a single 3 watt led . Plus the 19 mm ply top is used as a shelf for filaments & other consumables
Think the construction sheet was sub £30 and the single slide across front door sheet £ 11. ... it runs in four " F "shaped runners screwed to the ply at the top & bottom of the enclosure .
Being made of wood it's easy to screw bits to the sides & back if such things are required . So I've put in a 240 volt four switched outlet fused surge protected power bar & two baton bulb holders on the back wall . Bulbs are not just for illumination the y are left on 24/7 and act as a dehumidifier gentle warmth to the filament on the reel which is left in place on the printer .
Having left it as natural wood colour it's well lit with a single 3 watt led . Plus the 19 mm ply top is used as a shelf for filaments & other consumables
Think the construction sheet was sub £30 and the single slide across front door sheet £ 11. ... it runs in four " F "shaped runners screwed to the ply at the top & bottom of the enclosure .
Being made of wood it's easy to screw bits to the sides & back if such things are required . So I've put in a 240 volt four switched outlet fused surge protected power bar & two baton bulb holders on the back wall . Bulbs are not just for illumination the y are left on 24/7 and act as a dehumidifier gentle warmth to the filament on the reel which is left in place on the printer .
A few Days ago I printed some infill strips to go in the T-Slots on the cross slide of my Myford well it saves cleaning the slots lol. Now yesterday I changed over to a new roll of white PLA and all I kept getting was breakages so not happy. Someone told me to put the new roll of PLA in the oven for a "couple of hours" and that should fix the problem. So when the Sunday dinner is cooked I will bung the roll in the oven and see if it does the trick and stops the Breakages.
Screwdriver
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Gas or fan oven should be ok but needs to be around 50ºC or you'll end up with a sold lump.
Electric ovens are a bad idea because as the element is trying to push the average temperature up to 50º, the actual element itself will be at a vastly higher temperature. While a gas flame is also a much higer temperature too, it dissipates that that much more effectively into the volume of the oven. Don'e let the plastic anywhere near the flame of course...
Probably best to get it to temp then switch it off before putting in the plastic to dry out or soften. Place it on something non conducting!
Electric ovens are a bad idea because as the element is trying to push the average temperature up to 50º, the actual element itself will be at a vastly higher temperature. While a gas flame is also a much higer temperature too, it dissipates that that much more effectively into the volume of the oven. Don'e let the plastic anywhere near the flame of course...
Probably best to get it to temp then switch it off before putting in the plastic to dry out or soften. Place it on something non conducting!
