Everyone who 3D prints has parts that come out wrong: a first layer that won't stick, spaghetti halfway through a print, a spool that runs out. 3D print failures and waste cost real money, and they are a normal part of the craft, but if you don't count them, they come out of your pocket. Here is how to keep your own log to find your failure rate, how to spread its cost into each part's price, which causes keep repeating, and when it makes sense for the customer to cover a reprint.
3D print failures and waste cost: what one failure really costs
A failure costs more than the filament you throw away. You also lose machine hours, electricity, and wear for that stretch, and sometimes your own time to remove the mess, clean the bed, and relaunch the job. If a print failed at 90% progress, you lost almost the whole cost of the part. That's why it's worth measuring instead of guessing.
Lost material
The grams of filament that were printed and thrown away, including purge waste and failed starts.
Lost machine hours
Hours the printer ran without producing a sellable part. That time can't be recovered or invoiced.
Electricity and wear for that time
Even if the part fails, the machine used power and wore down. It's a real cost even when you have nothing to deliver.
Your time
Cleaning up, diagnosing, re-preparing the file, and relaunching. Minutes that add up without you noticing.
How to keep your own log to find your waste percentage
There is no waste percentage that works for everyone: it depends on your machine, materials, parts, and experience. That's why I won't hand you a 'typical' figure. What you can do is measure your own. A spreadsheet or a notebook where you note every failure and every job is enough.
Example failure log (hypothetical data)
| Date | Part | Grams lost | Hours lost | Cause |
|---|---|---|---|---|
| Week 1 | Medium stand | 60 g | 3 h | First layer didn't stick |
| Week 1 | Tall figure | 120 g | 6 h | Detached halfway up |
| Week 2 | Organizer | 90 g | 4 h | Clogged nozzle |
| Week 3 | Test part | 30 g | 1 h | Wet filament |
| Week 4 | Batch order | 180 g | 5 h | Spool ran out mid-job |
Adding up just the grams in this example table gives 480 g. If over those four weeks you printed, let's assume, 6,000 g in total (an assumption for the example), your material failure rate would be 480 ÷ 6,000 = 8%. Do the same with hours if you want a machine-time rate. Review your numbers each month and you'll see whether it goes down or up.
Failure rate over a period
How to spread failure cost into the price
Once you have your rate, a waste allowance is a fair way to spread the cost of failures across the good parts. The idea: if some parts out of every batch fail, the ones that come out well must also pay for the ones that didn't. The most accurate way is to divide the direct cost by one minus the failure rate.
Part's direct cost with waste already spread
With a hypothetical example: a part whose direct cost is 3.00 USD and an assumed failure rate of 8%. The cost with waste spread would be 3.00 ÷ 0.92 ≈ 3.26 USD. That's about 0.26 USD per part, an allowance near 8.7%. It looks small, but over hundreds of parts it's real money. Note you divide by 0.92 rather than adding 8%, because the cost of failures must also be covered by the parts that come out well. After this you apply your margin, as explained in the [3D printing margin guide](/en/blog/calculadora-margen-impresion-3d).
One long-part failure weighs more than ten small ones
If you print long, many-hour parts, a single failure late in the job costs a lot. You can apply a different failure rate to long jobs and short jobs, if your logs show they behave differently.
Common causes and how to prevent them
Causes repeat more than you might expect. If you note the cause of each failure in your log, you'll see which ones cost you the most and where to start improving. This is general prevention; every machine and material has its own quirks.
If you run several printers and many orders, also read [production mistakes in a 3D print farm](/en/blog/errores-produccion-granja-impresion-3d), which covers how to organize production so failures don't pile up.
When the customer covers the reprint
If the failure comes from your shop's process, the waste is already covered by the allowance you spread across the price, and it makes no sense to charge the customer separately. But there are cases where it's reasonable for them to cover the cost of reprinting, as long as you made it clear beforehand.
The customer's file has errors
If the model can't print well as it arrives and the customer asks to print it that way anyway, you can warn that a possible failure is on them.
Changes after approval
If they ask to modify the design when the print is done or underway, it's new work and it's quoted as such.
Tests or risky materials
If the customer demands a difficult material or an experimental setup, say beforehand that failed tests are charged.
What matters is that it is written in the quote or your order policy before you start. See [what to include in a 3D printing quote](/en/blog/que-incluir-cotizacion-impresion-3d) for where to put that condition. If you have legal questions about warranties or refunds in your country, check local rules.
Frequently asked questions
What waste percentage should I use in 3D printing?+
Should I charge the customer for my printer's failures?+
How do I work out what a failed print costs?+
Can my failure rate go down?+
Let waste travel inside the price
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