Metal 3D printing or CNC machining: which does your part need?

Choose CNC machining when your part is a solid, machinable shape that needs the tightest tolerances and a clean surface straight off the machine. Choose metal 3D printing when the geometry is too complex to cut: internal channels, lattices, consolidated assemblies, or shapes that would turn most of an expensive billet into chips. We run both processes at our workshop at 994 Bendemeer Road and quote them side by side, so the logic below is exactly what we apply when a metal part lands in our inbox.

How does geometry decide it?

Metal 3D printing fuses fine metal powder layer by layer with a laser, so the part grows instead of being cut. That is what lets it reach internal cooling channels, lattices and topology-optimised brackets that no cutting tool can. CNC machining works the other way: our 3-axis mills carve the part from solid stock, which suits blocks, plates, pockets, holes and flat mating faces. A rule of thumb we use daily: if you can picture holding the part in a vice and reaching every feature with a tool, machine it. If the interesting geometry is inside the part, print it. For the wider process map, see our guide on what 3D printing technology is best for you.

Which process holds tighter tolerances?

Machining. We hold down to plus or minus 0.05mm on CNC parts, with first-article inspection using digital calipers and pin gauges before anything leaves the studio. Printed metal parts are accurate, but where a face is truly critical we machine it after printing: print the complex form, then finish the datum faces on the mill. If every surface on your drawing carries a tight tolerance, machining the whole part is usually the saner route.

What do quantity and cost do to the decision?

Neither process needs tooling, so both suit one-offs and short runs. CNC parts start from S$80 per part, with volume discounts from 10 units (around 10 percent at 10 to 24 pieces and 20 percent at 25 to 99), and we are set up for 1 to 50 units rather than mass production. Metal printing is priced per job, not per gram, because the alloy, part size, density and finishing all move the number; we come back with a firm quote within 24 hours. The honest cost pattern: for simple solid parts, machining is nearly always better value. Printing earns its premium when the shape is complex, or when machining would waste most of the stock as swarf.

Does the material make the choice for you?

Sometimes, yes. Our CNC side runs aluminium 6061 and 7075, brass C360, engineering plastics like Delrin and POM, and hardwoods such as teak, walnut and oak. Our metal printing side runs stainless steels like 316L and 17-4PH, AlSi10Mg aluminium and Ti6Al4V titanium. Need brushed brass hardware or a teak casing? That is a machining job. Need a titanium bracket with a lattice core? Only printing gets there.

Should you prototype before committing to metal?

Usually. The cheapest way to check fit and form is a plastic print first: FDM runs about S$0.10 to S$0.30 per gram, so you can hold the part before spending on metal. Our FDM vs SLA vs SLS guide covers that choice. It is also worth asking whether the part needs to be metal at all. When a client needed a measurement fixture for small electronic connectors, we built the electronic parts holding jig in carbon-fibre reinforced PETG instead of machining aluminium: stiff and dimensionally stable enough for the job, with a shaped pocket, clamp and threaded insert at every station.

When is the answer neither?

Thin-walled metal enclosures are the classic case. For a custom stainless steel housing we cut the profile and cutouts from stainless sheet, rolled it into nested cylindrical sections, and fitted quick-release toggle latches and welded hinges. Printing that housing would have been slow and costly, and machining it from solid would have wasted almost the entire block. Because we fabricate as well as print and machine, we will tell you when sheet metal, or a mix of processes, beats both.

How do you get a straight answer for your part?

Send a STEP file with the critical tolerances called out and a line on what the part has to do. For CNC we reply with a quote and any design-for-manufacturability flags the same business day; for metal printing, within 24 hours. Talk to us with your file, or get an instant quote if a plastic prototype is the smart first step.