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A micro fabrication job

implmex

Diamond
Joined
Jun 23, 2002
Location
Vancouver BC Canada
Good morning All:
I just finished up a job making stainless steel micro injectors for a miniature plasma sprayer.
25 parts; the 3 wires on the end in the third picture are 0.015" diameter and 0.150" long welded to a 1/16" diameter tube
The back end with the orbital weld is an 0.093" OD tube with a 0.125" OD tube slipped over it and a 1/16" long step.

This was a super fiddly job but it came out pretty good, so I'm pleased with it.
Positioning the little wires to tack them onto the 1/16" tube was the whole trick, so I made a little jig to hold them in place and clamp them.
Lots of fun fiddling the wires into the jig under the microscope...there's dropped wires EVERYWHERE!

So; what do you think an assembly like this is worth?
- 3 wires tacked at both ends.
- Two annular welds with a positioning tolerance for the tubes of +/- 0.005"
- Overall length 18"
The customer was crying a bit about the price, but they couldn't find anyone else who would take it on in these low quantities, so they kind of had to suck it up.

Now they want a quantity discount because there's MORE!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 

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Good morning All:
I just finished up a job making stainless steel micro injectors for a miniature plasma sprayer.
25 parts; the 3 wires on the end in the third picture are 0.015" diameter and 0.150" long welded to a 1/16" diameter tube
The back end with the orbital weld is an 0.093" OD tube with a 0.125" OD tube slipped over it and a 1/16" long step.

This was a super fiddly job but it came out pretty good, so I'm pleased with it.
Positioning the little wires to tack them onto the 1/16" tube was the whole trick, so I made a little jig to hold them in place and clamp them.
Lots of fun fiddling the wires into the jig under the microscope...there's dropped wires EVERYWHERE!

So; what do you think an assembly like this is worth?
- 3 wires tacked at both ends.
- Two annular welds with a positioning tolerance for the tubes of +/- 0.005"
- Overall length 18"
The customer was crying a bit about the price, but they couldn't find anyone else who would take it on in these low quantities, so they kind of had to suck it up.

Now they want a quantity discount because there's MORE!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

Dude, the work I have seen you post, kind of scares the hell outta me. :)

Cool!

Cheers
Trev
 
Nice work. The micro welding is daunting to me, so without that knowhow, I couldn't price it. I'd be trying to think of something else, like perhaps crushing the tube into a triangular shape or something if that would work.
 
Hi Guys:
Actually with a laser welder, the welding itself is pretty easy.
The machine has a 40 power stereo microscope with a cross hair in one ocular, so it's literally point and shoot.
Just to get you in the picture, the orbital weld I show takes under 3 minutes to weld, so there is some positioning trickery necessary to align everything, but globbing it together is a doddle.

The real challenge is handling those damned wires.
The fixture I talked about is basically a disc into which I wire EDM cut a closed vee block with three radial slots at 120 degree increments to accept the wires and I have four thumbscrews; one for the tube and three for the wires.
So I place the tube and then thread a bit of wire into each slot , align it for axial position along the length of the tube and then pinch it with a thumbscrew.
Then I can laser tack it at both ends and pull off the jig.

Welding those is also the work of minutes, it's placing and aligning those teeny wires (never mind cutting them to accurate length and deburring them so they sit properly on the tube) that is the tricky bit.

The last operation is to stone the tops of the wires until the assembly can slide into a ring gauge...I have a tight tolerance on the diameter over the tips of the three wires (+0.000 -0.001").
After that I can slide it into the next bigger tube with a stop to hold it in position, tack it and then orbital weld it, and finally position the outside tube tack and orbital weld it too.

So I had to build a jig and I'll have to build a better one (Sometimes it's a fight to get the jig off the welded assembly, so I need to make one in two halves with a hinge and it'll be TINY).
Then I have to figure out a better way to make wires all to the same length and without burs, which probably means a jig for the wire EDM.
Then I have to get better at handling the wires...I'm OK at it by now, but there are still a lot of wires littering my floor that I'll never find again.

So I billed $125.00 CDN apiece for the first 25 parts and I did pretty good on it; about 50% better than my normal shop rate.
However, if I have to do hundreds a month I will go nuts doing them by hand under the scope and I might regret taking it on even though I'm greedy for the cash..
2 hours at a stretch is about my limit before I go cross eyed and start to fidget...days and weeks of this and I might be headed for the funny farm.

They'd like to pay more like 50 bucks apiece for these...I don't want to do them at that sort of price unless I can figure out a way to do them super efficiently without breaking the bank on fixtures and an automated laser.

So that's it in a nutshell.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

BTW if anyone wants to offer suggestions on how to fixture it more efficiently than I've described, I will be most appreciative to hear them!
MC
 
. . .So I billed $125.00 CDN apiece for the first 25 . . .

To be clear, I can't do that kind of work, but I my first thought was about double what you charged. I'd say the customer got his money's worth for a short run.

. . .They'd like to pay more like 50 bucks apiece for these . . .

Of course! And I'd like to pay $25 for a couple of shoulder replacements, but...
Really, you've got to make it worth both your time and your trouble. If you're hating life until the order is delivered, it probably isn't worth it.
 
Just wanted to double down on Marcus' laser welding. I've had one for more than five years and I still marvel at the precision of the welds. On the one I've got, the 'spot' size is adjustable between .2 mm and 2 mm. The larger spots are great for smoothing out smaller welds.

Ron
 
Hi Guys:
Actually with a laser welder, the welding itself is pretty easy.
The machine has a 40 power stereo microscope with a cross hair in one ocular, so it's literally point and shoot.
Just to get you in the picture, the orbital weld I show takes under 3 minutes to weld, so there is some positioning trickery necessary to align everything, but globbing it together is a doddle.

The real challenge is handling those damned wires.
The fixture I talked about is basically a disc into which I wire EDM cut a closed vee block with three radial slots at 120 degree increments to accept the wires and I have four thumbscrews; one for the tube and three for the wires.
So I place the tube and then thread a bit of wire into each slot , align it for axial position along the length of the tube and then pinch it with a thumbscrew.
Then I can laser tack it at both ends and pull off the jig.

Welding those is also the work of minutes, it's placing and aligning those teeny wires (never mind cutting them to accurate length and deburring them so they sit properly on the tube) that is the tricky bit.

The last operation is to stone the tops of the wires until the assembly can slide into a ring gauge...I have a tight tolerance on the diameter over the tips of the three wires (+0.000 -0.001").
After that I can slide it into the next bigger tube with a stop to hold it in position, tack it and then orbital weld it, and finally position the outside tube tack and orbital weld it too.

So I had to build a jig and I'll have to build a better one (Sometimes it's a fight to get the jig off the welded assembly, so I need to make one in two halves with a hinge and it'll be TINY).
Then I have to figure out a better way to make wires all to the same length and without burs, which probably means a jig for the wire EDM.
Then I have to get better at handling the wires...I'm OK at it by now, but there are still a lot of wires littering my floor that I'll never find again.

So I billed $125.00 CDN apiece for the first 25 parts and I did pretty good on it; about 50% better than my normal shop rate.
However, if I have to do hundreds a month I will go nuts doing them by hand under the scope and I might regret taking it on even though I'm greedy for the cash..
2 hours at a stretch is about my limit before I go cross eyed and start to fidget...days and weeks of this and I might be headed for the funny farm.

They'd like to pay more like 50 bucks apiece for these...I don't want to do them at that sort of price unless I can figure out a way to do them super efficiently without breaking the bank on fixtures and an automated laser.

So that's it in a nutshell.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

BTW if anyone wants to offer suggestions on how to fixture it more efficiently than I've described, I will be most appreciative to hear them!
MC

Is it possible to also cut the wires with your laser welder? What form is the raw wire stock? I'm imagining long pieces of wire. Load the 1/16" tube through the fixture, thread the wires through the slots, tack the front end of the wires, then pull it on through and cut the wires off with the laser and then weld that cut end.
 
You’re local to me Marcus, funnily enough for some similar work for maybe a mutual customer my first suggestion was to farm it out to you! :D
 
This is first rate work.That few are qualified to do.There are routine medical procedures that tens of thousands of doctors are qualified to do."EVERY" procedure cost thousands of dollars.Plus the consultant plus the nurse plus,plus plus.How many people can do what you are doing? I would think that most of the people that have laser, welders buy them for production jobs and are not interested in doing questionable job shop work. Don't work cheap.Edwin Dirnbeck
 
Hello Old Friend. Beautiful work, Marcus. Simply beautiful. While you did not lose money, I am firmly in the camp of those who assert that you under billed the work. Of course, I also know how easy it is to say so, from this side of the fence. ( and after the fact )

I tend to agonize over pricing jobs like this. Ones where you know that there are not many other places that can do all of these operations under one roof, nor have the experience, knowledge, or ability to do so even if they did. And yet..., in my mind ( our minds? ) we still know that it is a simple matter of time and effort expended, along with the balancing of what the customer expects. It's a tough balancing act.

Knowing all of that, I still think you under billed.

Kudos, Sir. Beautiful work, as usual.
 
So I billed $125.00 CDN apiece for the first 25 parts and I did pretty good on it; about 50% better than my normal shop rate.

:eek:

They'd like to pay more like 50 bucks apiece for these...I don't want to do them at that sort of price unless I can figure out a way to do them super efficiently without breaking the bank on fixtures and an automated laser.

:eek::eek::eek::eek::eek:

-----------------------------

I think $125 is a screaming price on those parts. It probably depends on the relationship with your customer as to whether you want to lower the price at all.

I think if it was me I’d say I can only do xxx per month (and explain why) and their still going to be $125/month.

If your the only vendor they can go to then your in the drivers seat.

Customers who pay COD may get some consideration, those who pay 60 days on 30 day invoices (and partial at that) get less consideration.

------------------------------

Outstanding parts, I used to work with one other person who might have been able to make those parts, that's out of 200-300 I've worked with over the years.
 
Good morning All:
I have received some really nice compliments and I appreciate them all very much.

The thing for me with jobs like these is that they often take a bit of experimentation to get in the groove, and that is the challenge (and the pleasure) of the job.

The thing about this job is that I cannot see a way to automate any part of it without an investment that's way outside reasonable for the commitment the customer is willing to make.
Doing it by hand as I've done on this first batch would be physically hard to do for an old fart like me if there are anything like the quantities the customer is dangling in front of me.

I needed a reality check about the prices I'm charging and for all who weighed in I'm grateful for your insight, and as I suspected, my prices are pretty modest.
However as we all know, there is a price point at which the amount of work you win starts to fall off drastically, and when I got the clear signal from the customer that I was well above that threshold, I started to second guess myself so I posted the query whether I was a greedy bastard or whether the customer was completely unrealistic about what a job like this is worth.

When I added up the hours I was most pleasantly surprised at how the job worked out for me.
If I could stand the fiddly tedium it'd be way better than much of what I do, so being the kind of personality I am, I thought "oh shit, I've ripped those poor bastards off" even though part of me knows perfectly well that there are not many places they could go to.
So the reality check was super helpful and I thank all of you for it!

With regard to your specific questions, Limy Sami, the notion of threading long wires, tacking one end and then somehow cutting them and tacking the other end occurred to me.
Sadly the idea of cutting them with the laser is not workable, 0.015" diameter wire is telephone pole sized for a 60 joule machine like mine, so I'd have to crank it way up to make the cut.
At those sorts of energies the pulse makes a messy splatter and blows a big divot out of the adjacent tube, so I tried modifying a side cutter and snipping them before welding.
Two problems with that approach: first, the side cutter scars the surface of the tube even with gentle and careful control under the scope, and second it makes a wedge shaped cut that is hard to weld...the end of the wire just turns into a blob rather than fusing consistently with the sidewall of the tube.
The cut ends need to be square for the tack to be predictable.
But it is a great idea in theory, and I appreciate you taking the trouble to articulate it.

So again, thank you all for the kind words.
Now I have to make a decision about just how badly I want the money.

Ahh, the joys of running a machine shop!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
I recently had an email conversation with Marcus enquiring about a small-scale wire edm job. I came away from it wiser and better educated as a result of his patient analysis, negative though it was, of what I proposed. The injector job that is the subject of his present thread reinforces the high opinion I formed of the quality of his work. It is work that deserves to be billed accordingly, as most have indicated above.

-Marty-
 
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