CNC Scrap Metal Prices: How to Handle CNC Metal Recycling

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  Key takeaways
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  Where CNC Scrap Comes From and Why It Grades Differently
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  What Actually Moves CNC Scrap Metal Prices
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  Setting Up Bins, Labels and Records in the Shop
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  Reading a Scrap Quote and Avoiding Common Mistakes
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  Six Steps to Sort, Clean and Sell CNC Scrap
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  Scrap Streams and How They Are Treated

Three streams come off a CNC machine. The first is chips and turnings cut from the workpiece. The second is solid skeleton material: plate offcuts, bar ends and the slug punched out of a turned part. The third is reject parts and test cuts that never ship. Each stream has a different buyer and a different price, so mixing them in one bin costs you money before the material ever leaves the dock.

Chips are the largest volume and the most price-sensitive. A finishing pass at 0.5 mm depth and 0.1 mm/rev feed produces fine, curled swarf. A roughing pass at 3 mm depth and 0.3 mm/rev produces short, heavy chips that drain better and read cleaner on the buyer's scale. Same alloy, two different prices. If your CAM programmer runs everything at the same parameters, the scrap bin shows it.

Solid offcuts are worth the most per kilogram because they carry no coolant surface area and no oxidation from the cutting zone. A 200 mm length of 7075 bar left over from a run is closer to new stock than to turnings. Many shops throw it in the chip bin out of habit. That is the single easiest loss to fix: a labeled rack next to the saw pays for itself in one job.

Reject parts sit in a gray zone. A part that failed a ±0.005 mm tolerance check is still clean, known alloy, and heavier than chips. As long as it has no plating, no insert and no customer marking, it belongs with solid scrap, not with turnings. Strip hardware first. A single steel helicoil in an aluminium reject can contaminate a whole barrel at the mill.

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  Chips and turningsHighest volume, lowest price per kilogram, most sensitive to coolant and mixing.
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  Solid offcutsBar ends, plate drops and slugs. Keep them dry and separated by alloy.
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  Reject partsClean, known alloy. Remove inserts, helicoils and any plated hardware before baling.
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  Swarf finesGrinding dust and filter sludge. Usually a lower grade; keep it out of the chip bin.

Alloy identity is the first and largest factor. Aluminium 6061 turnings, 7075 turnings and mixed aluminium turnings are three separate quotes. Stainless 304 and 316 are priced apart because of nickel and molybdenum content, and 17-4PH sits in its own band. If you cannot tell the buyer what alloy is in the barrel, the buyer assumes the lowest grade in the mix.

Contamination is the second factor, and it is the one you control. Coolant, way oil, floor sweepings, steel banding, plastic wrap and rubber seals all reduce recovery. A barrel that is 3% steel by weight can be rejected outright at a mill that runs aluminium. The fix is mechanical, not chemical: a chip spinner or centrifuge that brings residual coolant below roughly 2% by weight, plus a magnet pass before the barrel is closed.

Chip geometry and density matter for freight. Loose turnings occupy a lot of volume for their weight, so hauling them is inefficient. Briquetting or baling turnings into dense blocks raises the weight per truckload and usually earns a better rate. For a shop producing a few hundred kilograms a month this may not justify the equipment. Above a few tonnes a month, a briquetter changes the economics.

Market and logistics sit outside your control but still shape the number. Mill demand, freight distance and the buyer's own processing route all feed into the quote. What you can do is keep the material clean, dry, single-alloy and weighed, so you are negotiating on grade rather than on cleanup. Shops that sort well get quoted on the top band for their alloy. Shops that do not get quoted on the average.

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  Alloy identitySeparate 6061, 7075, 304, 316 and 17-4PH. One mixed barrel equals one low grade.
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  Residual coolantSpin or centrifuge chips to roughly 2% or less by weight before shipping.
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  DensityBale or briquette turnings to raise payload per truckload.
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  DocumentationAlloy, weight, date and source on each bin tag. Buyers trust traceable loads.

The cheapest upgrade is bin layout. Put a dedicated container at each machine or each cell, not one central dumpster. A 5-axis cell running titanium and a lathe cell running 303 stainless should never share a container, even for a day. Colour-code the bins and put the alloy name on the lid in characters at least 1.5 mm tall so it survives coolant mist and chips. Label the wall behind the bin too, so the label survives a bin swap.

Train the operators on one rule: when in doubt, stop and ask. A two-minute question about whether a part is 6061 or 6082 is cheaper than downgrading a 200 kg barrel. In practice, most mixing happens at shift change and during cleanup, when someone sweeps a bench into the nearest open bin. Close the bins or put lids on them. Open-top barrels collect exactly what you do not want.

Record every load. A simple spreadsheet with date, alloy, gross weight, tare weight and net weight is enough. Weigh on a floor scale rather than estimating from the number of barrels. When the buyer's scale reads differently from yours, you want a history to compare against, not a single disputed number. Photograph the closed and labeled barrels before the truck leaves; it settles most disagreements in one email.

Keep the paperwork with the material. If a load is ever questioned, alloy certificates from your own incoming stock, plus the bin tag and the weight record, show the load was single-alloy. Shops that run medical or aerospace work under ISO 13485:2016 or IATF 16949:2016 already keep material traceability for production. Extending that habit to the scrap bin costs almost nothing and protects the resale value.

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  One alloy per binDedicated containers at each cell. Never share across alloy families.
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  Legible labelsAlloy name and bin number, minimum 1.5 mm character height, on lid and wall.
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  Floor scale recordsDate, alloy, gross, tare and net weight for every load that leaves.
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  Photo before pickupClosed, labeled barrels photographed as they load out.

A scrap quote is a grade plus a weight plus a set of conditions. Ask the buyer what grade they are quoting and what contamination limit applies to it. A number without a grade is not comparable to another number. If one buyer quotes higher but applies a 1% steel limit and another quotes lower with a 3% limit, the better deal depends on how clean your barrels actually are. Measure that before you choose.

Ask how the buyer weighs. Some use their own scale at their yard, some weigh at pickup, some use your ticket. The difference is small per load but adds up over a year. If you weigh on a calibrated floor scale and keep records, you can spot a systematic gap early. Most disputes come from wet loads and mixed loads, not from scale calibration.

Watch for the three mistakes that show up again and again. First, storing turnings outside, where rain and oxidation drop the grade. Second, letting floor sweepings into the chip bin because it is faster at the end of a shift. Third, baling mixed alloy to save a barrel, which locks the contamination in permanently. All three are process problems, not market problems.

There is a limit to what recycling recovers. Chips will never fetch the price of new bar, and fines and sludge will never fetch the price of chips. The realistic goal is to move each stream into its correct grade and keep it there. That is a sorting discipline. It does not depend on the market being good, and it holds up when the market is bad.

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  Ask for the gradeA price without a grade and a contamination limit cannot be compared.
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  Confirm the scaleKnow whether the buyer weighs at your dock or at their yard.
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  Never store chips outsideRain and oxidation lower the grade before the truck arrives.
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  Do not bale mixed alloyOnce pressed, contamination cannot be sorted out again.