RFQ Small Cast Aluminum Cover

M.B. Naegle · Jan 25, 2021

I need to cast 50 of these 'U' shaped aluminum covers that go to a sewing machine we manufacture. We are looking at redesigning the assembly that this piece is part of in the near future to be made out of sheet metal, but in the mean-time need to fill some orders. The last aluminum foundry we worked with was in New York (closer to where our company used to be) but has closed.

This piece was cast iron when it was first designed (1910 or so), and at some point they switched to cast aluminum using the same patterns. The original board pattern was lost at some point and they started using some castings with the holes plugged as patterns. I'd like to continue using these pieces since the part will be changing soon, and it is not a dimensionally critical part. They are approx. 6" by 6" and stand 2" tall at the highest point, but are 1/8" thick shells for the most part.

Does anyone on here have any recommendations for a small quantity aluminum casting job like this? I'm happy to ship them anywhere, but closer to the greater Houston Texas area is preferred.

M.B. Naegle · Jan 25, 2021

I'll add too, that while I find back-yard casting interesting, I don't have the time or resources to do it right now.

Limy Sami · Jan 25, 2021

I'm not being a smartass, I did it out of curiosity - seem to be a couple of foundries in your back yard

aluminum casting houston - Google Search

M.B. Naegle · Jan 25, 2021

Limy Sami said:
I'm not being a smartass, I did it out of curiosity - seem to be a couple of foundries in your back yard

aluminum casting houston - Google Search

Thanks, I'm putting out feelers locally too.

I went through the local Google list for a different job (grey iron) a few years back and was very discouraged at how many local foundries either didn't want to touch low quantity work, or they had gone under but their listings were still active for some reason. I ended up finding one shop just down the road who seemed like the perfect fit, but then they did nothing with the job for a year and a half and kept giving me the run-around that they didn't have my contact information, didn't understand what I wanted, or were just too busy. I ended up using a foundry in Ohio who had the job done in a month better than I expected. I don't think they do aluminum though, so...

Hoping to get some feedback/experience from the guys on here.

D Nelson · Jan 25, 2021

Could it be 3D printed?
Don

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D Nelson · Jan 25, 2021

Or mim
Don

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dstig · Jan 25, 2021

I used these guys for alum prototype injection molds a number of years back, but they also do all sorts of low volume & prototype casting, including alum. They were pretty decent to work with. But local to me, not you...

Craft Pattern & Mold - Precision Prototyping for Plastic and Metal Parts

EmGo · Jan 25, 2021

Better call first, but I had lots of aluminum castings done by Castco in San Leandro, CA. Decent prices, good quality, timely delivery. They also do some material that is high in zinc, as well. Machines well and plates exceptionally nicely, if that matters.

I know a good fast patternmaker too, but he may have fallen over the edge ....

M.B. Naegle · Jan 26, 2021

D Nelson said:
Could it be 3D printed?
Don

Sent from my iPhone using Tapatalk Pro

We've considered getting a printer set-up in house, but we'd also have to have a scanner for a job like this as we don't have a CAD model drawn up yet and It has enough geometry to make it a chore to draw.

M.B. Naegle · Jan 26, 2021

A couple of the places I've looked at do Investment casting. For something like this I'd imagine they could scan it and print the wax pattern.

This is a $60 part once it's on the shelf, so we don't have much room to fund any pattern work or reverse engineering considering how few we would be making. Each of these more modern methods speeds things up but only after the initial investment. The old school green sand casting takes more time, but I'm inclined to think it would be cheapest given we could use our existing "patterns".

I spoke with one local foundry that wants me to bring the pieces by sometime, but they already said they would need a board pattern made.

I'm also looking at the improvements that will be going into the machine later. We were looking at having the next generation of this part made from sheet metal to keep costs down, but if making a board pattern is the only way to get it done, we might try to keep this part from changing. This part works with another cover on the machine and the sheet metal version would not be compatible with the older style set-up, so we do need to have something on the shelf to support the older machines. The machine has seen almost no improvement for 110 years, and a lot people like that, but it does need some 21st century upgrades as well as changes to keep up with modern manufacturing methods, so it's a balance between which parts stay fancy castings and which ones become cheap plastic.

TGTool · Jan 26, 2021

Could you make a quick and dirty matchboard for them using castings you have on the shelf? Using one casting to make another means the new ones are smaller by the aluminum shrink factor. That can be compensated on the male section maybe by spraying some build-up. Female not so much so you'd wind up with thicker walls by a little bit.

The match plate would have a recess in one side to nest one cover for the female side and the other cover on the opposite side accurately registered to match. The plate thickness would govern the final "flat" thickness. This all assumes that the draft on the existing covers is sufficient.

cosmos_275 · Jan 26, 2021

M.B. Naegle said:
We've considered getting a printer set-up in house, but we'd also have to have a scanner for a job like this as we don't have a CAD model drawn up yet and It has enough geometry to make it a chore to draw.

I think that's a one to two hour job to CAD it up. It doesn't look that bad unless the radii are critical to fit. Protolabs can do sheet metal and some metal printing, but I doubt they will be cheap.

Dan from Oakland · Jan 26, 2021

If you had a pattern at a foundry somewhere, 1st thing I would do is get on the phone and try to get your pattern back. You can't just walk in a foundry with a sample part and ask for castings. Getting a new pattern made is not the end of the world, but its not going to be free either. I can hook you up with a local foundry here that I have used for 20 years for my aluminum castings, but you will need that pattern or be willing to have one made.

dgfoster · Jan 26, 2021

From where I sit it looks like those pieces can be cast as simple loose pieces without any matchboard pattern being needed. The pattern itself would be placed in a flask flat side down and points up. Greensand or or bound sand would be packed around it. Then the cope flask just made would be flipped and the drag flask attached and packed. Now split the flasks apart, draw out the pattern, cut pour basin, runner and gates. Done. to speed up the process, a pattern for the gate, pour basin and sprue could be made and for a fifty run would make sense.

The shrinkage would be on the order of 1-2% in this part that the OP said was not diminsionally critical. If that shrinkage were a problem, the part sould easily be buiilt up using various paints, Bondo, Celastic etc. Sounds to me like the part itself would be fine.

If I had a bunch of small flasks (I don't) I'd do the job.

If the OP wants to contact me concerning what he expects to pay, I might consider the job.

Denis

M.B. Naegle · Jan 26, 2021

Dan from Oakland said:
If you had a pattern at a foundry somewhere, 1st thing I would do is get on the phone and try to get your pattern back. You can't just walk in a foundry with a sample part and ask for castings. Getting a new pattern made is not the end of the world, but its not going to be free either. I can hook you up with a local foundry here that I have used for 20 years for my aluminum castings, but you will need that pattern or be willing to have one made.

100% agree. We've had foundries in the past who insisted on keeping the patterns in their inventory so they could process orders faster. Once they realized that we simply didn't have that kind of volume and sent us our patterns back, one had termite damage :angry:

.

I'm not certain but I think the board pattern for this job disappeared when the aluminum foundry went under without us knowing and they just scrapped all the patterns that hadn't been claimed. This occurred before or after we had bought our company in 2006 and we were still in transition picking up all the loose ends. Now, we've started making wood cases for each individual board pattern when it ships out and we insist that it be sent back with the castings.

DDoug · Jan 26, 2021

These people are local to me, do short runs.
Arrow Castings - Home Page

But as said above, there has to be many shops closer.

Dan from Oakland · Jan 26, 2021

This is exactly why I never leave my patterns at the foundry. No production foundry is going to run your part loose in a flask. 20 years ago that might have been a possibility but in todays world, most foundries don't even have any molder who know how to run a lose pattern or hand mold a part. 99% of all low volume green sand molds are run on a jolt squeezer with a match plate because it requires less skill.

Illinoyance · Jan 26, 2021

I used to work for an elevator. They had a lot of patterns for sheaves. Maybe 50 to 100. They did not demand the patterns back from the foundry. The last foundry they used went bankrupt and all the patterns were lost. Each time they had to provide a replacement sheave they had to make a new pattern. So once you have your pattern made hang on to it. At some point you might want to change foundrys KIt is a lot easier to do if you have the pattern in your possession.

M.B. Naegle · Mar 2, 2021

Just a follow-up: I found a member on here who does some sand-casting of his own who took on this job (not sure if he wants to advertise the service so I leave that up to him). He did a little work to the loose patterns and sent the first two castings which machined and assembled without an issue, so the remaining castings will be getting poured later.

PM community for-the-win!

RFQ Small Cast Aluminum Cover

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