Cheap ODM Metal Die Casting Wholesale Deals: Where the Price Actually Comes From
A quote line is a sum of tooling, alloy, cycle time, trimming and machining stock. This page walks through each one so a design engineer or buyer can tell a lean quote from a thin one before the purchase order is signed.
What This Page Covers
Cost structure, part features that decide tooling price, and the checks that keep a low unit price from turning into a high total cost.
The Cost Structure Behind a Low Unit Price
Most die casting quotes look similar on the first page: unit price, tooling, lead time. The differences hide in the assumptions. A press running a four-cavity mold on a 1,200 t machine costs far less per part than a two-cavity mold on a 400 t machine, but the second setup often suits a part that must hold ±0.1 mm without a secondary operation. Cavity count, projected area and wall thickness set the machine tonnage, and tonnage sets the hourly rate.
Alloy is the next line. ADC12 and A380 behave differently in thin walls. ADC12 flows better in sections under 1.5 mm and holds detail around small bosses, while A380 gives higher ductility and better machining behavior after casting. Switching alloy to save a few cents per kilogram can add scrap at the trim press, which lands back in the unit price.
Then comes the part nobody quotes openly: machining stock. Castings are not finished parts. If a sealing face needs Ra 0.8–1.6 μm, someone has to cut it after the casting cools. Extra stock on that face means extra CNC time, and CNC time costs more per minute than casting time. We keep the stock minimal where the geometry allows it.
Freight and packaging rarely decide a contract, but they decide the delivered cost. Lightweight parts ship by volumetric weight, so a poorly nested carton can cost more than the casting. Ask how parts are nested and whether in-house finishing avoids a second shipping leg.
- 1Machine tonnageProjected area and wall thickness drive it, not part weight
- 2Cavity countMore cavities lower unit price but raise tooling cost
- 3Machining stockEvery millimeter of extra stock is CNC minutes
- 4Finishing locationIn-house anodizing or plating avoids a second freight leg
Part Features That Decide Whether the Deal Stays Cheap
A casting is cheap when the mold fills easily and the part ejects cleanly. Walls between 1.5 mm and 4 mm sit in that comfortable range for ADC12. Below 1.2 mm the alloy may not reach the end of the flow path before it freezes, and above 6 mm the section cools slowly, pulls porosity and needs more machining to reach a sound surface. Uniform walls beat thick walls every time.
Draft matters more than most CAD models admit. One degree of draft per side is the usual starting point; textured surfaces need two to three degrees because the texture grips the part. A casting with zero draft will be pried out of the mold by hand, and that shows up as a per-part handling charge or a scratched surface.
Ribs, bosses and fillets control shrinkage. A boss with a wall as thick as the adjacent wall becomes a hot spot and sinks on the opposite face. Coring the boss or thinning its wall to about 60 percent of the main wall keeps the cooling even. The same logic applies to fillets: sharp internal corners concentrate stress and slow the metal flow.
Undercuts are the fastest way to turn a cheap casting into an expensive one. Each side pull adds a slide to the tool, and slides need maintenance. If the undercut can be moved to a secondary CNC operation instead, the mold stays simple and the total cost often drops even though one more machining step appears in the routing.
- 1Wall thickness1.5–4 mm fills well in ADC12; below 1.2 mm risks short shots
- 2Draft angle1° per side plain, 2–3° on textured faces
- 3Boss wallAbout 60 percent of the main wall thickness
- 4UndercutsEach slide adds tool cost and maintenance
How to Compare ODM Die Casting Suppliers
Ask what happens after the shot. A supplier that casts, trims, machines and finishes under one roof controls the tolerance chain and the schedule. When the casting house ships raw parts to a separate machine shop, the second shop's queue becomes your lead time, and nobody owns the final dimension.
Tooling ownership is the second question. Confirm in writing who holds the mold, where it is stored, and what it costs to move it. A low tooling price sometimes means the mold is amortized into the unit price, which locks you to that supplier for the life of the program.
Then look at inspection. A 100 percent inspection before shipment with reports on request tells you the supplier measures parts rather than assumes the process is stable. For die casting, the critical checks are porosity at machined faces, flatness after trim, and thread depth on cast-in bosses.
Certifications narrow the field before you read a single quote. ISO 9001:2015 covers general quality management, IATF 16949:2016 applies to automotive programs, ISO 13485:2016 to medical hardware, and ISO 27001:2022 to data handling. If your drawings are confidential, the last one matters as much as the first.
- 1Single-site processCasting, machining and finishing in one plant
- 2Mold ownershipGet storage location and transfer terms in writing
- 3Inspection scope100 percent before shipment, reports on request
- 4CertificatesMatch the certificate to your industry, not the brochure
Casting Route vs. Machined-from-Solid Route
Use this when a low unit price depends on volume and geometry.
| Factor | Die casting | Machined from solid |
|---|---|---|
| Best volume band | 1,000+ parts per year | 1 to 500 parts |
| Tooling cost | Mold required, amortized over volume | None |
| Typical tolerance | ±0.1 mm as cast, ±0.005 mm after CNC | ±0.005 mm as machined |
| Wall sections | 1.5–4 mm uniform walls | Any, limited by tool reach |
| Porosity risk | Present in thick sections | None |
| Surface finish | Ra 1.6–3.2 μm as cast | Ra 0.8–1.6 μm typical |
| Change cost | Mold rework, weeks | Program edit, hours |
Reading Total Cost per Good Part
A cheap quote assumes a scrap rate. If the mold runs at 92 percent good parts and the next supplier runs at 99 percent, the second quote is cheaper per good part even at a higher piece price. Ask for the qualification rate the supplier plans to hold, then compare quotes on that basis. Our own target is 99.99 percent on inspected shipments.
Lead time carries its own cost. Parts that ship in 3–5 days keep a production line moving; parts that slip force expedited freight or a line-down event. A supplier with a historical late-delivery probability below 2 percent prices that reliability into the quote, and it is usually worth paying.
Volume breaks deserve scrutiny. A price that drops sharply above 10,000 pieces is often built on a faster cycle that trades tool life for output. Ask whether the mold is rated for the full program volume, and whether the price holds if the forecast changes by 30 percent.
The cheapest deal is the one where the part arrives in tolerance, on schedule, with the finish already applied. Everything before that is a quote.
- 1Compare per good partPiece price divided by qualification rate
- 2Check the scheduleLate deliveries cost more than the unit price
- 3Question volume breaksA faster cycle can shorten mold life
- 4Confirm scopeDoes the price include finishing and inspection?
Common Questions
Is a cheap ODM metal die casting quote always lower quality?
Not automatically. A supplier with a tighter process can quote less because less scrap and less rework are built into the estimate. The signal to watch is what the quote leaves out: machining stock, finishing, inspection reports or mold ownership.
What wall thickness should I target for a cast housing?
Between 1.5 mm and 4 mm for ADC12 works well in most housings. Keep walls as uniform as the design allows, and thin any boss wall to roughly 60 percent of the main wall so the thick section does not create a hot spot.
Can I get a casting without paying for a mold?
For very low volumes, machining from solid, vacuum casting or 3D printing avoids mold cost entirely. Die casting becomes the cheaper route once annual volume passes roughly 1,000 parts and the geometry suits a two-part mold.
How do you hold ±0.005 mm on a cast part?
The casting sets the rough shape, then CNC operations cut the critical faces. Tolerance of ±0.005 mm applies to machined features, not to the as-cast surface, which usually sits near ±0.1 mm.
How are my drawings protected during quoting?
Uploads are handled as confidential, and we sign a non-disclosure agreement on request before drawings are reviewed. Data handling is covered by our ISO 27001:2022 certification.
What is the minimum order quantity?
There is no minimum order quantity. Runs from a single prototype to 10,000 or more parts are quoted the same way, though the unit price changes with volume and cavity count.
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