Process comparisons

Which manufacturing process should you use?

Head-to-head manufacturing comparisons: molding vs casting, laser vs waterjet, MIG vs TIG, and more, each with cost, tolerance, and volume trade-offs.

Process selection

  • Injection Molding vs Die Casting: Pick injection molding for plastic parts where weight and unit cost matter, and die casting when the part must be metal for strength, heat, or shielding. Die casting tooling and machine costs run higher, so it needs volume to amortize.
  • Injection Molding vs 3D Printing: Use 3D printing for prototypes, low volumes, and complex one-offs, and switch to injection molding once volume is high enough that per-part savings pay back the mold, often a few hundred to a few thousand parts.
  • CNC Machining vs 3D Printing: Machine when precision, finish, and full strength matter; print when geometry is complex, volumes are low, or you want near net shape with little waste. Many shops prototype by printing, then machine the production part.
  • Thermoforming vs Injection Molding: Thermoform large, simpler parts at low tooling cost and moderate volume; injection mold small, detailed, high-tolerance parts at volumes that justify the mold.
  • FDM 3D Printing vs SLA 3D Printing: Default to FDM for functional prototypes, brackets, and shop fixtures where a 0.2 mm layer line does not matter. Switch to SLA when you need fine detail, an injection-mold-like finish, or casting masters. Many shops run both since combined entry cost is under $3,000.
  • SLS 3D Printing vs MJF 3D Printing: For PA12 production parts at quantities above a few hundred, MJF usually quotes 15 to 30% cheaper and turns builds faster. Pick SLS when the material list matters, when parts must be white or dyed a specific color, or when a $30,000 benchtop machine fits an in-house strategy.
  • Blow Molding vs Injection Molding: Geometry decides this one before cost does. A closed hollow body goes to blow molding; injection can only match it by molding halves and welding them, adding a tool and an operation. Everything else, especially anything with tight tolerances or engineered wall sections, goes to injection molding.
  • Rotational Molding vs Blow Molding: Volume and size make this call. Under roughly 3,000 to 5,000 units per year, or for anything bigger than about 1,000 L, rotomold it and pocket the tooling savings. Above that volume in a blow-moldable size, the 45 to 90 minute roto cycle can never compete with a 2 to 3 minute blow cycle.
  • Vacuum Casting vs Injection Molding: Vacuum casting is a bridge, not a destination. Use it for 10 to 100 units while the design settles or the injection tool is being cut. Once demand clears a few hundred parts, or the application needs true production resin properties, the numbers and the material data sheet both point to injection molding.
  • Compression Molding vs Injection Molding: Below roughly 50,000 parts per year, or for large fiber-reinforced panels, compression molding wins on tooling at a third the cost with better fiber strength. Above 100,000 parts of complex thermoplastic geometry, injection molding's 15 to 60 s cycles bury the bigger mold invoice. Between those volumes, quote both.
  • Plastic Extrusion vs Injection Molding: The geometry decides this one. If the part is a length of constant cross section, extrude it; nothing beats a $5,000 die and continuous output. If it has ends, bosses, or 3D features, injection mold it. Stop machining features into extruded stock past about 5,000 parts per year.

Cutting

  • Laser Cutting vs Waterjet Cutting: Choose laser for fast, precise cuts on thinner metals where a small heat zone is acceptable, and waterjet when the material is thick, heat sensitive, reflective, or non-metallic and a cold cut is required.
  • Plasma Cutting vs Oxy-Fuel Cutting: Buy plasma if you cut mixed metals or run production under 25 mm; the speed advantage is 3x to 4x and it handles stainless and aluminum. Keep oxy-fuel for carbon steel over 50 mm and remote field work. Most fab shops end up owning both for under $10,000 combined.

Joining

  • MIG Welding vs TIG Welding: Use MIG for fast, cost-effective welding of medium to thick steel in production, and TIG when weld quality, thin material, or exotic alloys demand precision and a clean bead, at the cost of speed and skilled labor.
  • Brazing vs Welding: Weld structure, braze assemblies. If the joint carries primary structural load in sections over 3 mm, weld it. If the assembly is thin-wall, mixes metals, needs 100 joints sealed at once, or cannot tolerate distortion, braze it, ideally in a batch or continuous furnace.
  • Riveting vs Welding: In high-volume steel, spot welding wins on cost and stiffness, which is why car bodies carry 3,000 to 5,000 spot welds. Choose riveting for aluminum-intensive or mixed-material structures, coated sheet, and anywhere heat distortion or weld inspection cost outweighs the $0.05 to $0.30 per fastener.
  • MIG Welding vs Stick Welding: Run MIG in the shop; three times the deposition rate pays for the gas bottle within weeks on any production schedule. Keep stick for wind, rain, rusty steel, and remote sites where shielding gas is a liability. A $500 stick machine backing up a MIG rig covers 95% of fabrication work.
  • Laser Welding vs TIG Welding: TIG stays the tool for repair, code pipe, and low-volume work with imperfect fit-up. Laser welding pays once you run repeatable joints in volume: 4x to 10x travel speed, almost no distortion on thin stainless, and operators productive in days instead of months. Fixturing discipline is the price of admission.

Casting

  • Sand Casting vs Investment Casting: Sand cast for large, cost-driven parts where a rough surface is fine, and invest in investment casting when detail, thin walls, and finish justify the higher tooling and per-part cost by cutting downstream machining.
  • Die Casting vs Permanent Mold Casting: Above roughly 10,000 parts per year, die casting wins on unit cost and thin walls. Choose permanent mold for runs of 500 to 10,000 parts, pressure tight castings, T6 heat treatment, or walls over 4 mm. If porosity or weldability matters, permanent mold is the safer default.

Finishing

  • Powder Coating vs Wet Painting: Powder coat metal parts that fit an oven when you want durability and low waste at volume; use wet paint for precise color matching, thin films, or parts too large or heat sensitive to cure.
  • Anodizing vs Powder Coating: Anodize aluminum when you need a hard, thin, integral wear surface and tight tolerances; powder coat when you need color choice, a thicker protective film, or a substrate that cannot be anodized.
  • Galvanizing vs Powder Coating: Specify galvanizing for structural steel that lives outdoors 25 years or more; nothing organic matches sacrificial zinc on cut edges and bolt holes. Specify powder coating when the part carries a color or the customer sees it. For coastal or heavy industrial exposure, run duplex: galvanize first, powder coat over it.
  • E-Coating vs Powder Coating: Powder coating wins for most job shops; the capital fits and polyester films handle UV. E-coat only pencils at automotive-scale volumes or when parts have interiors a spray gun cannot reach. If the corrosion spec exceeds 1,000 hours salt spray, price the duplex stack: e-coat primer under a powder topcoat.
  • Electropolishing vs Passivation: Passivation is the default for machined stainless: cheap, no dimensional change, meets ASTM A967. Step up to electropolishing when the print calls a microfinish, when edge burrs matter, or for sanitary and high purity service. Never electropolish features toleranced tighter than ±0.025 mm without budgeting the stock removal.
  • Bead Blasting vs Sand Blasting: These are not interchangeable. Bead blast for appearance and pre anodize work where dimensions must hold; blast with aluminum oxide or garnet for scale removal and coating prep where you need a 2 to 4 mil profile. Never run actual silica sand; OSHA silica exposure limits make it a liability.

Machining

  • CNC Milling vs CNC Turning: Turn round parts and mill prismatic ones. Parts with both round and prismatic features often run on a mill-turn machine or move between a lathe and a mill in sequence.
  • EDM vs CNC Milling: Mill first, EDM last. Rough and semi-finish everything before heat treat on the mill, then send only what milling cannot do to EDM: hardened cavities, sharp corners, deep ribs, and wire-cut punch and die profiles. Shops that EDM millable features are paying $80 to $120 per hour for nothing.
  • CNC Router vs CNC Mill: Buy the machine that matches your material, not your budget. A router earns its keep nesting sheet goods and aluminum panel at 10,000+ mm/min across a 4 by 8 ft bed. The moment the print says steel or shows +/-0.025 mm, only a mill's cast iron and torque will hold it.
  • 5-Axis Machining vs 3-Axis Machining: Start with 3-axis unless your part list says otherwise; it machines prismatic work at roughly half the hourly rate. Move to 5-axis when parts routinely need three or more setups, when re-fixturing eats the tolerance budget, or when contoured aerospace and medical geometry is the business you are chasing.
  • Broaching vs Milling: Run the volume math. A $6,000 keyway broach against 4 minutes of mill or slotting time at $85/hr pays back around 1,000 to 1,500 parts. Below that, mill it, shape it, or wire EDM it. Above 5,000 parts per year, nothing else touches broaching cost per feature.
  • Swiss Machining vs CNC Turning: Under 32 mm diameter, past 3:1 length to diameter, and above roughly 1,000 pieces, Swiss wins on both tolerance and cost per part. Large diameters, short parts, and small lots belong on a CNC lathe. Do not pay 4 hours of Swiss setup for 100 pieces of easy geometry.

Metal forming

  • Forging vs Casting: Forge parts that carry high or cyclic loads and cannot tolerate porosity, and cast parts whose geometry is too complex to forge or where tooling budget and part size favor pouring.
  • Servo Press vs Hydraulic Press: A hydraulic press remains the right answer for deep draws, tryout, and job-shop tonnage on a budget. Pay the servo premium when you stamp high-strength steel, need in-die dwell or restrike, or run volumes where an extra 20 to 40 strokes per minute changes what the plant can ship.

Sheet metal

  • Stamping vs Laser Cutting: Stamp when volumes are high enough to amortize the die and you need speed and formed features; laser cut for low to medium volumes, prototypes, and designs that change, where zero tooling wins.
  • Roll Forming vs Press Brake Bending: Run the annual meters. Below roughly 15,000 m per year per profile, the press brake's cheap tooling and fast changeover win despite 5 to 15 s per bend. Above that, a $25,000 to $80,000 roll set pays back within a year and drops labor per part by 80 to 90%.
  • Hydroforming vs Stamping: This is a volume decision. Under roughly 5,000 to 20,000 parts per year, hydroforming's single die half at $30,000 to $120,000 beats a $300,000 stamping set the press never amortizes. Past that, stamping's 1 to 3 s cycles win decisively. Prototype in hydroform, productionize in stamping.

Material selection

  • Aluminum Fabrication vs Steel Fabrication: Default to steel when cost and stiffness rule; A36 at $0.70 per lb with a 200 GPa modulus is hard to beat for frames and weldments. Switch to aluminum when every pound saved earns money back in fuel or payload, or when bare corrosion resistance deletes an entire finishing step.
  • Hot Rolled Steel vs Cold Rolled Steel: Buy hot rolled for structure and anything fully machined; the 15 to 25 percent savings is free when scale and gauge do not matter. Buy cold rolled for sheet metal work, cosmetic surfaces, and tight forming. Watch cold rolled parts with asymmetric machining: locked in stress makes them move.

Heat treatment

  • Annealing vs Tempering: This is a sequence question, not either or. Anneal when you need soft, machinable, stress free material going into the process. Quench and temper when you need final properties coming out. Never skip tempering on quenched steel; as quenched 4140 at 55+ HRC will crack in service, sometimes within hours.

Last reviewed 2026-05-12.