Quick Answer
Exhaust your sourcing options before you print a replacement.4 If a part can still be ordered from a vendor, it is very rare for it to make economic sense to 3D print it.4
When a part truly cannot be found, printing can turn a long wait into a same-day fix.2 Waiting weeks for a replacement part can be frustrating and costly.2
This guide covers fused deposition modeling (FDM). It is one of the most common processes for making plastic parts, alongside stereolithography (SLA) and selective laser sintering (SLS).1 It focuses on polylactic acid (PLA), which is stiff and easy to print.6
Who This Helps
Downtime adds up fast, whether you maintain equipment or keep an older machine running.2 A missing knob, bracket or cover can stop the whole job.
Custom and replacement printing is aimed at homeowners, collectors, and restorers who want something specific.3 Most 3D printers are used to make plastic parts.1
What Counts as a Printable Part
Custom and replacement 3D printing means making a one-off piece or a hard-to-find spare part, layer by layer, from a digital model instead of buying it off a shelf.3
Restorers use the fun term “unobtanium” for parts that truly cannot be sourced.4 Printing one involves some investment, so these parts are of high value.4
Requests range from a stove knob to a replacement chandelier crystal.4 Dr3amToReal, a design-led 3D printing studio in Aveiro, Portugal, recreates discontinued or hard-to-source parts, including classic-car components.3
Step-by-Step Process
Whatever the part, the approach to a printed replacement is largely the same.4
Step 1: Search Before You Design
Depending on the part, an online forum or a junkyard may supply a replacement.4 Exhaust sourcing options like these before you consider printing.4 There is some investment involved in getting a printed replacement.4
Step 2: Make a Digital Model
Printing starts from a digital model.3 A photo or measurement of your part can be the starting point for a made-to-order object.3
Photograph and measure the broken original before you throw it away.
Step 3: Pick the Material
The materials used in modern FDM printing are more than adequate for most household replacement parts.6 PLA is stiff, easy to print and suitable for decorative or low-stress applications.6
Common FDM materials include PLA and nylon, and these are durable and easy to work with.5 Dr3amToReal prints each piece with FDM in a choice of materials that includes PLA.3
Step 4: Test, Then Print
Dr3amToReal designs, tests, and prints every piece to order.3 Copy that habit.
Step 5: Finish the Surface
FDM parts usually lack a consumer-ready finish.5 If the part will be visible, budget extra time for finishing.
Budget-Friendly Options
Stay with plastic. Metal 3D printers are available, but at a substantially higher cost.1
Printing on demand replaces slow supply chains and expensive warehouses full of spare parts.2 It lets you produce what you need, exactly when you need it.2
If you do not own a printer, ask a studio. Dr3amToReal makes pieces to order and explains what custom printing costs and how to commission a piece.3
Sourcing comes first. Forums and junkyards cost little, and a part you can still order is rarely worth printing.4
Common Mistakes
- Printing a part you can still order from a vendor.4
- Using PLA for demanding jobs, when it suits decorative or low-stress applications.6
- Expecting a finished look straight off the printer, since FDM parts usually lack consumer-ready finishes.5
- Paying for metal printing when a plastic part will do, given the substantially higher cost.1
- Skipping a test fit before the part goes into service.
Safety and Limits
Treat parts for vehicles and expensive equipment as high stakes. If one is broken or missing, it can leave the machine non-functioning and useless.4
Keep PLA for decorative or low-stress jobs.6 For anything heavier, do not assume the plastic will cope. Ask a printing studio before you fit it.
Quick-Reference Checklist
- Check vendors first; printing rarely makes economic sense for orderable parts.4
- Look on forums and at junkyards.4
- Photograph and measure the original.3
- Choose PLA for decorative or low-stress parts.6
- Consider nylon as another common FDM material.5
- Stay with plastic printing to control cost.1
- Test the fit before relying on the part.
- Plan time to finish the surface.5
- Treat vehicle and equipment parts as high stakes.4
- Remember that printing can turn a long wait into a same-day fix.2