Sheet Metal Factory

Separate and store the different scrap materials (stainless steel, aluminium, etc) and regularly sell them to a recycling company. 40 gallon drums work well. It is not uncommon to get metal recycle companies to come to you with trucks to pick up your old scrap material and pay you for it. Your factory output is probably not large enough to consider melting the material down to ingots for easier storage, or a small recycling department to separate different material waste.

Material waste should be able to be separated at the CNC or punching stage (when only one material is being worked with at a time, especially in a production run), and placed in clearly marked storage drums for easy classification and disposal.

Without more information it is difficult to advise how to reduce your metal wastage, but you should consider looking into cutting the large scrap sheet from one process and reusing the scrap metal in a smaller process to reduce waste. Consider cutting sheets of material into smaller shapes that minimise scrap waste (using metal guillotine, etc).

And don't forget, recycle, recycle, recycle and save $$$!

Do you have part numbers for any of these items? Do you have computers?

How do you do it now?

First optimize layouts to reduce unused area by Nesting. Preventing waste is always better than trying to remediate waste.

Second, Consider making two parts at once one of the smaller in an unused area the same time that you are making a larger one.

Third, If a band of metal is created along one edge, you could hand feed that into a simple press to make washers. Once you have created say, 5 million or so of these washers, as a separate remedial stand alone operation, you will realize the truth in my first two statements above.

Welcome to manufacturing!

milo

Thank you Milo. I would accept the Idea of Using simple press as you mentioned for making washers. You 've emphasized almost this same idea that really came up into my mind, but the issue of the high cost of producing washers on punching machine was confusing.

Now we have to add a press for producing washers and like. Would you kindly help in suggesting some types and specifications of such presses to select from. We want to produce good engineered standard washers.

"the issue of the high cost of producing washers on punching machine was confusing." The material is virtually free, it is a sunk cost. It is worth whatever you would have recovered as scrap.

I was being somewhat facetious with the idea of producing the washers, as it will in fact be an inefficiency. And who knows what demand there will be for such washers?

However, if you can recover more than the sum of cost of the labor to punch them, and the cost of the tooling, utilities, and depreciation on the press, then you can do it. IF YOU HAVE A MARKET FOR THE WASHERS.

HAve you researched that your scrap material is made of proper material and grade to produce "Good engineered standard washers?"

milo

Hi Eng Nagi. You must manage your area. Create part numbers for all your parts. That way you will know if any changes were made and that you are using the latest drawings for punching. No mistakes, no waste. The person doing drawings can use open areas on the sheet to punch more than one job at the same time. If off-cuts are left, then use them with smaller items as the CNC can utilise smaller material and not just full sheets. Make sure your bending operator knows the exact bend he/she will make as bending the wrong way result in waste material. Make sure each job is listed and documented. Rather make one or two more of an item instead of sitting with lots of off-cuts, only with jobs you know will be ordered again. Little pieces that are left over, bin them and sell them to metal dealers as scrap thus getting some funds back, making sure they don't get mixed up as aluminium is more expensive than mild steel. Hope this helps a bit.

Sheet metal waste seems to be a hard issue to control. It's more efficient to grab a full sheet to make your parts then it is to dig through the scraps to find a suitable piece.

Some of these people are suggesting "nesting." I think they might be assuming that you have a CNC operated laser or plasma cam available where you can layout how the parts are to be cut out and fit everything together to get the most from each sheet. That's kind of hard to do if the sheets are handled by hand and cut to size using a sheetmetal shear.

Another way to help reduce waste is to maintain lower levels of inventory on your sheet metal in the first place. It's a Lean Manufacturing practice that says that by reducing the amount of inventory you have on hand makes the amount of mistakes made more visible because the workers don't have the inventory to cover up for their mistakes so they work harder to avoid making mistakes. Fewer mistakes makes for less waste.

Only keep scrape down to a certain size. When they're too small, you can't use them anyway. Try to maintain a list of scrape so programmer know what they can use without spending 30 minutes looking for it. You need to decide how many scrape you want to keep. Maintaining and moving them is part of your running cost. At some point it'll be more cost effective to throw them away.