That First TPU Molding Quote
It was March of last year. A Tuesday morning. My inbox had a quote from a vendor we'd been talking to about a new TPU molding project. The number looked reasonable—almost too reasonable. I remember thinking, finally, a straightforward bid.
The project was a custom polyurethane part—a protective boot for a sensor assembly we were launching in Q3. We'd done similar parts before in nylon and HDPE, but TPU (thermoplastic polyurethane) was new to us. The quote said $2.80 per unit for a run of 2,000 parts. Tooling: $4,000. I forwarded it to my boss with a note saying, looks good.
That note aged poorly.
Where the Quote Hid Its Teeth
Our standard process at that point was to get two or three bids and go with the lowest total. So I did what I'd always done: got three quotes. Vendor A: $2.80/unit. Vendor B: $3.15/unit. Vendor C: $2.95/unit. Vendor A won. Easy.
Then the first invoice arrived. It was for $4,850.
I said TPU molding, standard setup
and they heard TPU molding with material certification, plus a rush on tooling qualification
. Result: a $450 bill for material cert documentation—paperwork the engineer didn't even ask for—and a $400 expedite fee
on tooling setup.
Looking back, I should have asked for an itemized cost breakdown. At the time, I was so focused on unit price and tooling that I didn't think about the rest. And—honestly—I didn't know what questions to ask.
What We Missed in Plastic SCM
We didn't have a formal request-for-quote (RFQ) checklist for custom molding jobs. We had a general one for standard plastic parts—our PVC and HDPE pipe fittings—but TPU molding is different. Material grade matters. Cycle time changes. Secondary operations are common. We were using the same words but meaning different things. Discovered this when the parts showed up with a surface finish we didn't want and a per-unit cost that had creeped up to $3.25 after required
post-processing.
I didn't just get burned on that first order. I got singed twice—once on cost, once on specifications.
The Real Cost of TPU Molding
After that debacle, I started tracking every line item. Over the next 12 months, we ran four more TPU projects with different vendors. Here's what the numbers told me (based on actual invoices from 3 U.S. molders, Q2 2024; verify current rates):
- Base unit price: $2.50–$4.00 for typical TPU parts (60–90 durometer, medium complexity). This is the number everyone quotes.
- Tooling: $3,000–$8,000. Depends on cavity count, material (P20 steel vs. aluminum for prototype), and whether you need injection or compression molds.
- Hidden costs: Material certification ($200–$500), first article inspection (FAI) reports ($350–$700), secondary operations like deflashing or overmolding ($0.50–$1.50 per part), packaging customization.
- Setup fees: Many molders charge $75–$200 per color or material changeover. One vendor didn't mention this until after the first run—
standard practice,
they said. It was an additional $150 per changeover we did. (Note to self: negotiate changeover costs upfront.)
In one case, a vendor quoted $2.65/unit. By the time we added FAI, material cert, and a minor post-mold trimming step, the effective cost was $3.30/unit—25% higher than the headline number. That 25% is the difference between hitting your budget and explaining an overrun to finance.
How We Fixed Our Plastic SCM Process
The third time we got surprised by an unexpected
cost, I stopped blaming the vendors and started looking at our own process. We didn't have a formal approval chain for custom molding projects—no standard RFQ template, no cost tracking spreadsheet. Cost us when an unauthorized $600 material upgrade
appeared on an invoice because an engineer made a phone call without checking with procurement.
So I built a simple RFQ checklist. It asks for:
- Material grade (specific TPU durometer, not just
TPU
) - Cycle time estimate
- Fees for FAI, material cert, and any secondary ops
- Changeover costs for multi-material runs
- Shipping terms (FOB vs. delivered)
Then I created a cost calculator in Excel. It takes the unit price and adds up every variable I can think of, using historical data to estimate likely adders. That spreadsheet lives on our shared drive now. Any engineer asking for a quote has to fill it out first.
What We Found After Tracking 18 Orders
After tracking 18 custom molding orders across 6 vendors over 14 months in our procurement system, I found that 23% of our budget overruns
came from unacknowledged material or secondary operation costs. We implemented a policy requiring vendors to quote all expected adders in writing before any PO is issued. That alone cut our overrun rate to under 8%.
We've been meaning to document this process formally as a standard operating procedure (SOP) for the whole team. I really should do that before the next new hire.
The Lesson: Total Cost Matters More Than Unit Price
If I could redo that first TPU negotiation, I'd spend less time haggling on per-unit price and more time asking what else is included?
But given what I knew then—which was based on our experience with standard PVC and HDPE parts, where tooling and unit price covered 90% of the cost—my approach was reasonable. I just didn't know what I didn't know about custom materials.
Now I do. And our plastic SCM process is better for it. The next TPU project we quote—and there's one coming up for a different product line—I'll use the checklist, I'll ask for the itemized cost breakdown, and I'll calculate the total cost before I say looks good.
I won't say I'll never get burned again. But if I do, at least I'll know exactly where the fire started.