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Establishing a supply chain for your product + finance/accounting questions.

OH!

You are getting your stock ground to thickness because YOU DON'T HAVE A TOOL CHANGER!!!!

Now it all makes sense.

Get yourself back to HGR and scare up something that changes tools for you for $5000, and this whole problem goes out the window.

I know this, because I started with a knee mill as well so many years ago. It's fine for a few, but absolutely cuts you off at the knees trying to make production quantities.

You have to optimize around minimizing tool changes, so you can't optimize around other things. With a tool changer you can almost certainly just use standard bar stock to make the same parts.

That's the problem you need to solve, not using a complicated supply chain with lasers and grinders to make blanks.
 
I think you should consider NDA'ing someone knowledgeable and showing them what you're doing and ask them for advice.

I was the laser supervisor for the largest stainless consumer in California. What issues were you having with the laser cutting? Edge quality? Tolerance? Oxidation? Unfortunately lasers suffer from a similar issue as other machine tools in the sense that the lense & nozzle wear out and get dirty similar to how a tool dulls; except usually a dull tool gets swapped early, but a dirty lense & nozzle can simple be left in place to make coarser cuts. This is common on steel parts, especially thicker material where oxygen is used as the cutting gas. On the flip side of that laser cutting has become outstandingly good with high quality fiber lasers and you can hold pretty nice tolerances, so long as you have a way to deal with the edge/oxidation/lead-in.

Man... I ran a ProtoTrak bed mill for a while, because "it's easier to prototype with than with a VMC.".
LOL.
I think it's great you have the paid-off machinery to make these for materials cost, but if you grow in volume, the time savings are probably comically good with a real VMC. I bet my Speedio would run our "it's faster" CNC bed mill parts that took ~10 minutes in about ~8 seconds. Once you account for tool changes, tool break detection, tool life measurement, positional accuracy, spindle speed, it's a different world. It's good that you can bank that cash for now, and that it's an easy possibility to up your production in the future, even if it's just buying a cheap Fadal.
 
With regards to the company selling your product always make sure you never stop selling yourself. There are countless reasons for why a customer can suddenly stop buying. I went with the path of least resistance and due to the company I was supplying not marketing the sales dropped off. Your sales should at least be the bread and butter and everything else is cream.
 
Yeah, I had wondered that as well:

Why are you buying strips of material at all?
I would fully expect that the laser joint would put a full sheet i the machine, and git out of it all that it can.

I understand that we don't see what you see, and I understand that you need to be vague as well, but I'm not following your BOM thought process at all?


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I am Ox and I approve this here post!

I have never tried the laser cut blank method. I have always bought the material in long strips equal to the width of my blanks and then cut them to length on the saw.

The laser idea came to me while dealing with the material supplier who couldn't get my stock dimensions right. I thought; "hey, what if I get the laser shop to pre-cut all these for me out of plate and eliminate all this sawing?" I was thinking one piece of material would be easier to order and I'd just have it drop shipped to them. As you guys pointed out, I was half right. Yes on the laser, no on supplying the material myself.


For each assembly, you need 120 blanks? So for 200 assemblies a month, you need to process 24000 pieces?
No, the size and quantity I provided is enough for 600 assemblies.

On the other hand, if that 120 blanks is the total quantity needed to do your runs of 200 per month, then just buy a used medium sized 3 axis power feed surface grinder and do it in house after laser cutting. Have your laser cutter buy the material as a full sheet.
I was just looking at surface grinders on HGR's site thinking the same thing. You have a good point about the material too. If I just have them get a full sheet, I'm pretty sure they will keep it on hand and pull it when I need something cut.

Cutting charges from sheet suppliers suck, and they're rarely willing to quote tolerances, much less actually deliver them.
Isn't that the truth. It would've been like $3000 to have them cut the blanks complete. Does anyone actually pay them for that service?

Are the parts hardened? Is that why 4140?

Do you need through hard? Can you use carburizing or nitriding?

I ask because there are other, more common materials than 4140.

Yes, they are hardened and very prone to wear. I use 4140 a lot because I know I can trust it. There are hundreds of these in use with years of operation on them and zero wear. I wouldn't want to risk messing with that - plus the nitride vendor keeps losing my stuff and it pisses me off.
 
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I was just looking at surface grinders on HGR's site thinking the same thing. You have a good point about the material too. If I just have them get a full sheet, I'm pretty sure they will keep it on hand and pull it when I need something cut.

I think you're in my neck of the woods if you want to stop by some evening and try running a batch on my grinder to see if that's a workflow that works before you splash out the money. Have you run a surface grinder before?

I'm out of town at the moment but will be back in a couple weeks. The shop's in Hudson. My grinder for this sort of thing is a Kent 1632AHD
 
You are getting your stock ground to thickness because YOU DON'T HAVE A TOOL CHANGER!!!!

Now it all makes sense.

Get yourself back to HGR and scare up something that changes tools for you for $5000, and this whole problem goes out the window.

I know this, because I started with a knee mill as well so many years ago. It's fine for a few, but absolutely cuts you off at the knees trying to make production quantities

You're not kidding. Dude I am so tired of manual tool changes, it's brutal.

I have a vmc, I just don't have it running yet, that's a whole different though.

Either way, I'm going the EDM route with these parts so I will still need to grind the plates. I am with you though, an auto feed surface grinder can take care of that.


I was the laser supervisor for the largest stainless consumer in California. What issues were you having with the laser cutting? Edge quality? Tolerance? Oxidation?

I might have questions in the future if you don't mind. I design parts for laser on occasion but it's hard to find people I can ask for help in that arena.

As for these parts, they really need to be EDM cut. They need a nice, clean profile that is perpendicular to the face.
 
You have a good point about the material too. If I just have them get a full sheet, I'm pretty sure they will keep it on hand and pull it when I need something cut.

I (we?) was thinking that you would just get the whole sheet ran up at once.
That will be by far your best price.
I wouldn't expect that they would want to keep several customers 1/2 sheets about?

But then, I used to keep a block of Rex76 at the EDM shop, and they would burn out of it for me here and there.
May still have some there for all I know?


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I am Ox and I approve this here post!
 
You're not kidding. Dude I am so tired of manual tool changes, it's brutal.

I have a vmc, I just don't have it running yet, that's a whole different though.

Either way, I'm going the EDM route with these parts so I will still need to grind the plates. I am with you though, an auto feed surface grinder can take care of that.




I might have questions in the future if you don't mind. I design parts for laser on occasion but it's hard to find people I can ask for help in that arena.

As for these parts, they really need to be EDM cut. They need a nice, clean profile that is perpendicular to the face.


You are wanting to grind these plates BEFORE you mill them apart?


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Think Snow Eh!
Ox
 
I (we?) was thinking that you would just get the whole sheet ran up at once.
That will be by far your best price.
I wouldn't expect that they would want to keep several customers 1/2 sheets about?

But then, I used to keep a block of Rex76 at the EDM shop, and they would burn out of it for me here and there.
May still have some there for all I know?


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I am Ox and I approve this here post!

I'm not sure. It says "material stocking" under services on their website.

This is who I've been using the last few years.
They have good prices and delivery that could compete with Amazon prime. I have gotten parts delivered the day after I approved the order and they are on the other side of the state, down below Dayton.

You are wanting to grind these plates BEFORE you mill them apart?


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Think Snow Eh!
Ox

Yes, but they don't really get milled apart. Think about grabbing a piece of plate in a vise and milling washers out of it - as many washers as will fit in the plate. Drill a hole in the center of what will be each washer, drill a start hole for your end mill, and then mill out the washer which falls free from the plate.

Take the washer over to the belt sander to knock the tit off that was left from cutting it free and then throw it in the tumbler. This is basically what I'm doing except I'm not making precision ground washers... I'm making precision ground something else lol.
 
Drill a hole in the center of what will be each washer, drill a start hole for your end mill, and then mill out the washer which falls free from the plate.
Sounds like a lathe and grinder job. Or is there something I'm missing.
 
You're not kidding. Dude I am so tired of manual tool changes, it's brutal.

I have a vmc, I just don't have it running yet, that's a whole different though.

Either way, I'm going the EDM route with these parts so I will still need to grind the plates. I am with you though, an auto feed surface grinder can take care of that.




I might have questions in the future if you don't mind. I design parts for laser on occasion but it's hard to find people I can ask for help in that arena.

As for these parts, they really need to be EDM cut. They need a nice, clean profile that is perpendicular to the face.
Yeah feel free to reach out any time, happy to help within the bounds that I can.

Frankly I know that we're talking about wire EDM's here, but this sounds like it might be a bar fed lathe part to me, ideally. Done-in-one machining, to spec, of a part that was able to be run on a knee mill? Bar fed lathe.
 
Sounds like a lathe and grinder job. Or is there something I'm missing.

Sorry for the confusion. I was using washers as a simple example to visualize the operation - milling a profile from a plate. The parts I am making are not round at all.
 
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I think you're in my neck of the woods if you want to stop by some evening and try running a batch on my grinder to see if that's a workflow that works before you splash out the money. Have you run a surface grinder before?

I'm out of town at the moment but will be back in a couple weeks. The shop's in Hudson. My grinder for this sort of thing is a Kent 1632AHD
Thank you, that would be great. Yes, Hudson isn't too far from me. I spent a lot of time in Stow when I was a kid.

I have run surface grinders but not much. I know how to dress a wheel and grind something flat-ish and square-ish; but by no means would I consider myself to be skilled in grinding.
 
With regards to the company selling your product always make sure you never stop selling yourself. There are countless reasons for why a customer can suddenly stop buying. I went with the path of least resistance and due to the company I was supplying not marketing the sales dropped off. Your sales should at least be the bread and butter and everything else is cream.

Great point. Yes, I plan to continue selling them myself as well.
 
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Actually, anything that you can doo in a mill, you can doo in C axis on a lathe.

I just seen a pic of low pro gas blocks done on a mill.
I run them on a lathe.


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I am Ox and I approve this here post!
 
I don't want to go into the details of the customer's business. However, the mutually beneficial nature of our relationship is transparent. Our businesses are complimentary, not competing. I know how many units they need and while I am running these, I will be designing the next one they need as well. I have very little concern about the stability of our agreement.

I do know the market very well. They have a much bigger retail presence than I do. They also have a much larger selection of inventory which attracts a larger portion of the customer base.

Worst case scenario, a year or two from now, they tell me that they no longer want to continue selling this product. I finish the run, sell them myself and keep on going with the next thing.
"mutually beneficial nature of our relationship is transparent." Yeah, that's how most marriages start out so there is that.
Most of the guys offering advice know thier shit about working metal and so forth so you will get some good advice....all I have to offer is find a lazer cutter who you can talk to and get quotes based on the minimum you need and then a quote based on you lazer guy doing one set-up on his table with material he has on hand especially if he runs his jobs lights out.
 
You might try TCI Precision Metals, tciprecision.com
From their website:
Made to order blanks
Custom made to your specs, near net size to your finished part
Flat, square, and parallel
As close as +/-.002“ flatness and +/-.0005” dimensionaly
From one to thousands, your material or ours

I have no idea if they would be cost effective for you.
 
Are you sure you can't do the whole blank on the laser? If you can get a vendor to cut slow and pay attention, you can get amazing cut quality on steel on a fiber laser. I've been buying laser parts for 20+ years. But I finally got my own fiber laser and I am blown away at the cut quality I can get if I go with the quality cut settings and then spend some time dialing things in. It's too soon for me to put numbers to it, but it's looking like +-0.001 on feature size on 1/4" steel is doable. You have to be very mindful of putting pieces and leadins where they won't matter. And tabbing is a challenge. But it only takes changing my cut conditions from S1 (fast) to S3 (quality) and accepting 1/3rd the feed rate. Getting features that are perpendicular to the surface would require good slats.

But most shops won't do this. They only want to do fast.
 
Are you sure you can't do the whole blank on the laser? If you can get a vendor to cut slow and pay attention, you can get amazing cut quality on steel on a fiber laser. I've been buying laser parts for 20+ years. But I finally got my own fiber laser and I am blown away at the cut quality I can get if I go with the quality cut settings and then spend some time dialing things in. It's too soon for me to put numbers to it, but it's looking like +-0.001 on feature size on 1/4" steel is doable. You have to be very mindful of putting pieces and leadins where they won't matter. And tabbing is a challenge. But it only takes changing my cut conditions from S1 (fast) to S3 (quality) and accepting 1/3rd the feed rate. Getting features that are perpendicular to the surface would require good slats.

But most shops won't do this. They only want to do fast.

I suspected that was the case but I would have never guessed that +/- 0.001" in 1/4" material would be possible, that is seriously impressive.
 








 
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