Seeking Metal 3D design and prototyping Resource(s)

[MadScientist]

Greetings!

I am new to this forum, with no 3D printing exposure or experience.

For one of my biology garage projects, I need help with figuring out who can rapid prototype a miniature metal iris diaphragm with razor edges for cutting soft biological material.

The requirement specifications I've come up with are:

Max radius of iris diaphragm =~ 0 mm

Max radius of iris diaphragm = 2 mm

Sharpness for cutting neatly through soft, pliant biological material

Resistant to corrosion from aqueous environment

Resistant to frequent blade dullingWithstand repeated usage (at least ~10K, preferably 1MM cycles)

Easily scalable to fabricate more numbers

After prototype validation, design should be compatible with multiplexing, i.e. a grid of such devices with common control(s)

Easy-to-use controls to set max radius

Simple manual mechanism to effect the cutting action

If this is the wrong forum or page within the forum, could you please guide me in the right direction? Thank you!

[2fprototypes]

Do you have drawings?

[MadScientist]

Do you have drawings?

Thank you for your response.

Do I have the design ? No not yet.

Since I posted here, I came to learn that an iris diaphragm that is well designed and well fabricated should NOT ever have a minimum aperture of 0 (zero). For example, see this link - https://tinyurl.com/y7n6n8wt, from PL equipment, making this claim, pertaining to motorized optical iris diaphragms.

On the flip side, I have this other link from Eksma Optics - https://eksmaoptics.com/optical-syst...is-diaphragms/, that suggests there are indeed zero aperture iris diaphragms. But as discussed in the previous link as well, I think there are special cases, that "consist of 2 parallel planes of blades which can fully obstruct the light."

Question 1
So which of these 2 claims is correct!? And is zero aperture OK in terms of design, fabrication and use through 10 - 100K cycles?

Not knowing the answer to this question has paused my work. Unless a sharp-edged internal aperture, consisting of iris diaphragm blades, goes down to 0, the soft biological material within it will not get sliced into two clean pieces.

Question 2
The other question a colleague raised is whether each of the blades in an iris diaphragm is at a marginally different height, thereby eliminating even the possibility of a clean cut one would obtain from a guillotine mechanism. This would be especially true if a 0 aperture design would require 2 planes of blades.

If it'll be like chad hanging from a sheet of paper on which a 3-hole punch worked, but did not slice through 100%, then such sample processing would be an outcome defeating the very purpose of this entire exercise.

Design Resource
However, if you think engineering logic does indeed support the validity of zero aperture iris diaphragm, AND processing the sample with a neat cut, then I can buy this cheap subscription to https://iris-calculator.com/. On this website, it does allow the aperture to be zero, though it asks for confirmation.

If you or anyone on this forum can help me make a call on these questions, then I am happy to play around on this website, pay for subscription, generate the 'DXF file' and then attempt to convert that to an STL file, which is one of the file formats used by 3D printers, right?

Look forward to your advice. Thanks!

[curious aardvark]

the other thing to bear in mind is the complexity of an iris mechanism versue a standard extrusion/guillotine approach.
Three bladee, some complex gearing.
Lot to go wrong - particularly if it's being run for long periods.

Also bear in mind that 3d metal printing is EXPENSIVE !
Whereas a tube with guillotine is pretty cheap and easy to make.
Okay so you need to change out the tube to change the diameter of the sample being sliced - and I can see where an iris would be of benefit there.

I like the idea but can's see how to make it work. If the blades were all on the same plane, then they would blunt each other, ending up in a smush rather than a cut.

There is a compnay that specialises in tiny metal printed widgets who might be able to make something- wouldn't hurt to ask. Now I just need to try and remember who the hell they are !

Well that's annoying - they were at the tct in 2017 - and I did notm,ention the company name in my thread :-(
Guess I'll have to go though the last couple of years of acquired leaflets.

Actually kjust looked through the show guides :-)

Digital metal are the chaps !
https://digitalmetal.tech/
have a chat with them

[MadScientist]

Thanks very much for suggesting https://digitalmetal.tech/Just curious, how expensive is expensive? 100s, 1000s, 10000s or more? I have no idea.

In my mind, I preferred metal over plastic because of longevity and my doubts whether a cutting edge in plastic would work at all (would it?), but I suppose there is a large trade-off against cost and ease of fabrication?

Based on the sum total of all misgivings, I am completely moving away from this iris diaphragm idea.I need ANY mechanism that can cut my sample.

Perhaps the attached image will help us visualize the problem better. Currently, I place the sample on it's side, against a hard surface, and slice it with a scalpel - but it is way too laborious for processing more than ~ 100 samples at a time, whereas I need 1000s at least. Also image is not to scale, and is at least ~ 10X larger than the real sample (as you would have noticed, the samples are germinated seedlings, much like sprouts in a sandwich).

The cut plane shown as a red arrow is perpendicular to the longitudinal axis at the cut plane shown as a blue dotted line, and the cut position itself is visually determined to be just below where the bulge in the sample becomes significantly greater than it is (below the greener leafy sort of region).

So if some widget can sort of thread this sample through a hole of a certain (fixed or adjustable) radius, and then allow me to cut it where the increase in it's radial thickness prevents it from passing through anymore, with some blade mechanism, that would make things faster. But suggestions of any other mechanisms are also welcome.

Based on your useful advice, I feel I've put the proverbial (3D printing) cart in front of the (design) horse. So, in terms of soliciting conceptual solutions to my problem (even before design and fabrication) what are good forums to seek such help? Here and/or elsewhere? Please advice. Thank you!

[curious aardvark]

Ah - right I was envisaging a continuous cylinder being sliced into sections.
Individual seedlings, yeah that's a serious handling problem.

What you want is a robotics forum.
Cheap robotic arms could probably be taught to do this task.
And there are some really useful and relatively cheap arms around.

You'd need to design a special gripper/hand/holder for the seedlings and a feeding system - which is where the 3d printing comes into play.
But for the actual job itself - you need a robotic arm or two :-)

My knowlefe on such things is pretty sketchy. But I do remember seeing a kickstarter recently about one with easy to change 'tools' and a simple learning curve.
this kind of thing: https://www.kickstarter.com/projects...rial-robot-arm
quick glance shows a lot of them around.

So you need a bunch of roboticists to tell you which one can do what you want and to actually write the software and artificial intelligence routines to make it work :-)

[MadScientist]

Thank you for that suggestion. And also for the link to Mirobot's KickStarter.

That sounds a little pricey though, for my garage project Especially if I need 2 Mirobots = $600+. hmmm... but do not want to rule anything out yet, when the manual option is such a pain in the neck, literally!

I'd always imagined robotization of a manual process would involve machine vision apart from mechatronics. Since your robotization suggestion did not include optics, I suppose you envision the cutting position and plane to be determined by the mechanized 'feed mechanism; itself, right?

Just that I cannot envision what such a "feed mechanism" would be like. Any ideas, please? Or links to any specialized forums where I can seek such 'design' help?

Thanks a LOT!

[Ankeruhrbj]

Ah - right I was envisaging a continuous cylinder being sliced into sections.
Individual seedlings, yeah that's a serious handling problem.

What you want is a robotics forum.
Cheap robotic arms could probably be taught to do this task.
And there are some really useful and relatively cheap arms around.

You'd need to design a special gripper/hand/holder for the seedlings and a feeding system - which is where the 3d printing comes into play.
But for the actual job itself - you need a robotic arm or two :-)

My knowlefe on such things is pretty sketchy. But I do remember seeing a kickstarter recently about one with easy to change 'tools' and a simple learning curve.
this kind of thing: https://www.kickstarter.com/projects...rial-robot-arm
quick glance shows a lot of them around. mcdvoice survey

So you need a bunch of roboticists to tell you which one can do what you want and to actually write the software and artificial intelligence routines to make it work :-)

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[tommyshelbyop]

Ah - right I was envisaging a continuous cylinder being sliced into sections. Individual seedlings, yeah that's a serious handling problem. What you want is a robotics forum. Cheap robotic arms could probably be taught to do this task. And there are some really useful and relatively cheap arms around. You'd need to design a special gripper/hand/holder for the seedlings and a feeding system - which is where the 3d printing comes into play. But for the actual job itself - you need a robotic arm or two :-) My knowlefe on such things is pretty sketchy. But I do remember seeing a kickstarter recently about one with easy to change 'tools' and a simple learning curve. this kind of thing: https://www.kickstarter.com/projects...rial-robot-armmcdvoicequick glance shows a lot of them around. So you need a bunch of roboticists to tell you which one can do what you want and to actually write the software and artificial intelligence routines to make it work :-)

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