PLA, stainless steal and the nightmare it has caused me

This may not look like much, but it took me over a year, countless drill bits, and copious amounts of cutting fluid to produce a completely polished, 2mm ID in a stainless steel M6 rod for better PLA extrusion. I found the secret is a #48 parabolic flute drill bit, from both ends followed by a 2mm straight flute drill bit, kind of like a reaming bit, all the way through to get rid of the parting line. Then, a .094" spiral wire brush coated with wet Ajax in to polish it. This ought to get you PLA loving ecohippies off my back.

Very nice,I to have roasted many a drill bit trying to make these. Might I ask where you purchased the parabolic drill bit and 2mm straight flute drill bit?

mcmaster-carr #'s 2912A224 & 8842A43. About $13 plus shipping.

Thanks, will give it a shot.

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ohioplastics
This ought to get you PLA loving ecohippies off my back.

I'm a bit puzzled about your communication model. Do you think that insulting your potential clients/users will improve their confidence in your products ?

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Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.

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DeuxVis

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ohioplastics
This ought to get you PLA loving ecohippies off my back.

I'm a bit puzzled about your communication model. Do you think that insulting your potential clients/users will improve their confidence in your products ?

Its a joke, people use pla because it is easier to print with(less warping and no heated bed), not because its eco friendly, ABS is actually a lot easier to recycle than pla, infact pla does not really biodegrade without special processing.

Ok then if that was humorous, maybe try to get it a little bit more obvious.


I believe humour is one of the first thing lost when crossing cultural boundaries.

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Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.

I'm confused,

Is this a complicated procedure? due to such a small hole in stainless which is hard to machine?

If there is a real need for this?

Why hasn't some tried a single blast of a Laser or Water cutter with the right kerf?

Edited 1 time(s). Last edit at 01/20/2014 11:31AM by ShadowRam.

I can't speak for the laser cutter, but a water cutter tends to leave too much of a chamfered cut. The problem I have found is that if you look down a hole drilled with a regular jobber drill bit, there will be a series of concentric circles left from the drilling operation. These ridges equate to an increase in friction when the filament is pushed through.

And the problem with regular reaming bits is they tend to snap like dry twigs when you try this with steel, although it's technically possible.

This is a bit off subject but i thought id share it.

My dad who was a lifelong machininst told me a story one time about the competitiveness between the Germans and Swiss in regards to manufacturing long ago. Suposedly a German company created what they thought was the worlds smallest drill bit and mailed it to one of their swiss competitors to show off what they could do. The swiss drilled a small hole through the side of the drill bit and mailed it back.

it takes a bit of practice at drilling these kinds of holes in stainless steel like this especially when it's bee rolled on the outside to make it even slightly harder,

you mostly want to use the cobalt based drill bits for a longer drill life time, but sometimes it's easier and cheaper to get a cnc shop to do it since the federates are much more controlled as well as coolant delivery

i am looking at building an edm drill press pretty soon for doing similar holes to this but smaller

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The Swiss are too busy fussing with their watches and pocket knifes to produce anything lately.

But maybe I just take the German's side cause I'm German.

So now pla extrudes smoothly? Curious about how polishing a surface can improve the performance of pla extrusion. Would be good if somebody can shed some light.

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chngyian
So now pla extrudes smoothly? Curious about how polishing a surface can improve the performance of pla extrusion. Would be good if somebody can shed some light.

Coefficient of friction.

What grade of stainless was used?. 303 SST machines a lot easier than the more common 18-8 (304) and still offer good wear properties.

M6 thread rod is only available in 18-8 and 316, as far as I know. 18-8 was used.

Edited 1 time(s). Last edit at 01/23/2014 06:25PM by ohioplastics.

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greenman100

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chngyian
So now pla extrudes smoothly? Curious about how polishing a surface can improve the performance of pla extrusion. Would be good if somebody can shed some light.

Coefficient of friction.

is this the reason why j heads with pfte liner extrude PLA smoother?

the question i think that really needs to be asked is " why are we trying to push a low melting point plastic through hotends designed for high much higher temperatures?"

while it is possible to build an all metal hotend that can extrude PLA to a fairly good degree of reliability (and i have), in practice it comes down to the PLA itself, I've seen the stuff go through various different hardnesses ,smells and extrusion temperatures, and even today while the diameter of most of the Chinese stuff is fairly good it's still changing in composition from batch to batch quite wildly, what's happening is that producers are bulking it up with fillers which change the behavior of the plastic itself especially in all metal hotends, ptfe liners have been our saving grace due to the coefficient of friction alone.

to me it comes down the the right tool for the job, "an extrude it all" hotend is a bit of fantasy at this point in time however in the future when the industry demands much tighter quality control over the filament then it might be worth looking at again, until then people really should start getting used to the idea of having multiple hotends for different materials

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thejollygrimreaper
to me it comes down the the right tool for the job, "an extrude it all" hotend is a bit of fantasy at this point in time however in the future when the industry demands much tighter quality control over the filament then it might be worth looking at again, until then people really should start getting used to the idea of having multiple hotends for different materials

I'm curious as to why you think this? I have been very happy with my E3D hotend as my "extrude it all" hotend. I change between different filaments all of the time but the hotend hasn't been removed in over 3 months. PLA works beautifully with it. I have no stake in E3D, I'm just a guy who has tried many hotends and am happy that my search is over.

I second tkole in that the E3D design pretty much extrudes everything I feed it with. The massive crowd feedback/development cycle they conducted in this forum might have to do with the high reliability, I guess, as there were times where people had problems extruding this or that material and reported it for the developers to fix. So in a way, we also have to thank each other (or more specificly, the early adopters) for helping to refine a solid hotend. Again, such projects show the capability and speed of open source & development, but I begin to stray off topic here...

Edited 1 time(s). Last edit at 01/24/2014 11:46AM by uGen.

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tkole

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thejollygrimreaper
to me it comes down the the right tool for the job, "an extrude it all" hotend is a bit of fantasy at this point in time however in the future when the industry demands much tighter quality control over the filament then it might be worth looking at again, until then people really should start getting used to the idea of having multiple hotends for different materials

I'm curious as to why you think this? I have been very happy with my E3D hotend as my "extrude it all" hotend. I change between different filaments all of the time but the hotend hasn't been removed in over 3 months. PLA works beautifully with it. I have no stake in E3D, I'm just a guy who has tried many hotends and am happy that my search is over.

mostly out of experience and my own testing in the past, "PLA works beautifully with it" is something i hear quite often ,but which brands/color/size? not all PLA filament is created equal at the same time,

with the E3D, Sanjay has done quite well with his design and the aggressive cooling on the E3D and he has created something very close to to the "extrude it all" hotend, it depends on who you talk to as to reliability with extruding PLA with it,

PTFE liners allow certain benefits over all metal one and vice versa, what i did notice is that you generally get better control over extrusion with a ptfe liner eg, start ,stop , consistency you also don't get the tipping point problem either (where you have a lowest speed limit which your filament can run through the hotend before it jams due to heat going up the filament (but thats solved for the most part by increasing the speed))

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It's about efficiency and cost effectiveness. People shouldn't have to pay $80 for an all stainless steel hot end when all you really need is 1" of M6 rod. It's a $2 part.

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thejollygrimreaper
"PLA works beautifully with it" is something i hear quite often ,but which brands/color/size? not all PLA filament is created equal at the same time

Protoparadigm (black, red, orange, silver, forest green), Ultmachine (orange, black, red), Jet (black, red, orange, silver). All 3mm diameter with 0.4 mm nozzle diameter. Printer is running around 12 hours per day without any problems for several months. That freedom from headache is definitely worth $80 to me.

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ohioplastics
It's about efficiency and cost effectiveness. People shouldn't have to pay $80 for an all stainless steel hot end when all you really need is 1" of M6 rod. It's a $2 part.

price is another whole area entirely, $80 is a bit much

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uGen
such projects show the capability and speed of open source & development, but I begin to stray off topic here...

yes... only because Sanjay listened to feedback, the general thread wasn't the place to do that though and as a result it's been quite beneficial to him, be nice if some of those more critical dimensions were published though eg inside the nozzle

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ohioplastics
It's about efficiency and cost effectiveness. People shouldn't have to pay $80 for an all stainless steel hot end when all you really need is 1" of M6 rod. It's a $2 part.

And a several thousand dollar laithe. If I had one of those I would make my own hotend.

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tkole

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thejollygrimreaper
"PLA works beautifully with it" is something i hear quite often ,but which brands/color/size? not all PLA filament is created equal at the same time

Protoparadigm (black, red, orange, silver, forest green), Ultmachine (orange, black, red), Jet (black, red, orange, silver). All 3mm diameter with 0.4 mm nozzle diameter. Printer is running around 12 hours per day without any problems for several months. That freedom from headache is definitely worth $80 to me.

nice , however those are considered to be higher end brands of filament so no surprises there,

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thejollygrimreaper
nice , however those are considered to be higher end brands of filament so no surprises there,

I agree with protoparadigm and ultmachine being highend but I wouldn't consider Jet in the same category. $29 shipped if you have amazon prime and it usually arrives in 1 to 2 days. It's not my primary brand but it helps when you are in a pinch. No offense Jet, whoever you are.

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tkole
And a several thousand dollar laithe. If I had one of those I would make my own hotend.

I sell them for $2. It's $0.23 worth of material if you do it yourself. $2 is an %800 percent markup minus ebay fees. Pretty standard for most machine shops. And when you demistify it, it's just a piece of metal with a hole in it.

Edited 1 time(s). Last edit at 01/24/2014 03:45PM by ohioplastics.

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tkole

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thejollygrimreaper
nice , however those are considered to be higher end brands of filament so no surprises there,

I agree with protoparadigm and ultmachine being highend but I wouldn't consider Jet in the same category. $29 shipped if you have amazon prime and it usually arrives in 1 to 2 days. It's not my primary brand but it helps when you are in a pinch. No offense Jet, whoever you are.

i mostly run some of the cheaper chinese stuff,

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