How should this part be made?
How should this part be made?
A drawing does not always point to one manufacturing process.
Material, geometry, tolerances, annual volume, tooling, finish, testing, and timing can move the same part toward machining, casting, stamping, fabrication, molding, electronics assembly, or a combination of processes.
Choosing the process too early can lock the program into unnecessary tooling, cost, lead time, or redesign work.
The seven inputs that usually drive process selection
1. Material and performance
Start with what the part must withstand: load, impact, heat, chemicals, electrical requirements, environmental exposure, weight, and expected service life. A material callout without the performance reason can narrow the options before the tradeoffs are understood.
2. Geometry and size
Wall thickness, undercuts, cavities, ribs, bosses, holes, bends, draft, enclosed sections, and overall dimensions affect tooling and process access.
3. Tolerances and critical features
Separate truly critical dimensions from general drawing tolerances. Tight control everywhere can make a part harder and more expensive to quote than necessary.
4. Annual volume and order pattern
Prototype, short-run, mid-volume, and high-volume programs support different tooling and production economics. Include expected annual quantity, release size, and program duration.
5. Tooling and change risk
If the design is still changing, a process with lower initial tooling commitment may deserve review. If the design and demand are stable, production tooling may support a better unit-cost path.
6. Finish, assembly, and documentation
Coating, plating, cosmetic surfaces, heat treatment, cleaning, welding, inserts, assembly, testing, traceability, inspection, packaging, and certifications can change the manufacturing route.
7. Timing and supply path
Prototype timing, production launch, capacity, domestic or offshore preferences, and supplier risk all belong in the process decision.
Common paths to compare
| Process path | Often reviewed when | Questions to settle |
|---|---|---|
| CNC machining | Geometry or tolerances need direct material removal, design is changing, or volume is limited | Material, stock size, machine access, tolerances, finish, cycle time |
| Casting | Metal geometry, consolidation, or production volume may justify tooling | Alloy, wall sections, porosity, draft, machining allowance, volume |
| Stamping | Sheet-metal parts have repeat volume and geometry that can support tooling | Material, thickness, blank size, forming, tolerances, annual volume |
| Sheet metal fabrication | Parts need cutting, bending, welding, hardware, or enclosure assembly | Gauge, bend radii, welds, hardware, finish, quantity |
| Injection molding | Plastic parts may support production tooling and repeat volume | Resin, wall, draft, undercuts, cosmetics, tooling, volume |
| Rotational molding | Larger hollow plastic parts or low to mid-volume programs need review | Resin, wall, inserts, finish, size, volume |
| Thermoforming | Sheet plastic housings, covers, trays, or larger formed parts may fit | Material, draw ratio, trim, texture, wall distribution, volume |
| Electronics or electromechanical assembly | The requirement includes PCBAs, harnesses, cables, box build, or integration | BOM, drawings, test, traceability, components, volume |
This table is a screening tool, not a manufacturability decision.
When to compare more than one route
A comparison is especially useful when:
- The design is early
- The quote feels high
- Annual volume is changing
- A current supplier cannot meet timing or quality needs
- Tooling has not been committed
- The part combines metal, plastic, electronics, or assembly
- The buyer is unsure whether domestic, offshore, or mixed production fits
- A second source is needed
What to send Lupton
Send the drawing, material, annual volume, critical tolerances, finish, testing, documentation, timing, and anything that is still open.
Lupton reviews the requirements and helps identify the questions that should be settled before the project enters the appropriate manufacturing and quote path.
Start the review
Not sure which process fits the part?
Ask questions first through the website assistant, or send the drawing and project requirements for formal review.
FAQs
Is the lowest piece price always the best process choice?
No. Tooling, secondary operations, scrap, testing, freight, inventory, change risk, quality, and timing all affect total program cost.
Should I choose the process before sending an RFQ?
Not always. If the design is early or more than one process may fit, send the performance requirements and expected volume with the drawing. The manufacturing review can then test the assumptions.
Can the same part be quoted through two processes?
Sometimes. A comparison may be useful when geometry, material, volume, or tooling economics support more than one route. Each shop must confirm whether the part fits its process and capacity.
What if the annual volume is uncertain?
Provide a reasonable low, expected, and high range along with release quantities. That helps distinguish prototype, bridge, and production paths.
Want to discuss the project?
Book time with our team to review the part, process questions, volume, timing, or current sourcing issue.