Estimate for plastic injection moulded design?

Hi everyone,

I need some tips on calculating a budget for the design and development of an industrial product.

I participated in a design pitch for an injection molded product and my design was chosen. Having spoken to various plastic manufacturers I know that my design is suitable for this particular technique, but the exact design needs to be developed further and delivered to the manufacturer in a usable format.

My client now wants me to give him a quote for the further development of the design. I do not need to include estimates for the actual manufacture of the design.

I plan to include estimates for the following:

  • Research
  • General design
  • Technical preparation for construction
  • Presentations / Meetings with the client
  • Support / management during test production phase
  • Travel expenses
  • Office expenses

Have I overlooked anything? Are there things in there that shouldn’t be?
Is there anyone with specific plastic injection-mould experience who can warn me of potential pitfalls or other details?

Thanks in advance,

“but the exact design needs to be developed further and delivered to the manufacturer in a usable format.”

you have liability insurance?

yes i do :laughing:
i guess you are an experienced industrial designer, with knowlegde of the injection moulding process. So maybe you could share some of your experience?


wouldnt know where to begin. depends on project.

issues come to mind include: tools locking up (closed) bc steel deflection. fill problems forcing tooling people to shut off runners. run unbalanced molds. deliver one of two parts/cycle and lose alot of money. disrupt assembly cell timing. design w poorly located gates causing bad knit lines. and structural problems. among other things.

my advice is subcontract engineering and have them look over your work.

All help is appreciated!

My client will deal with the process of the actual manufacturing.
I will work on the process of making the final and detailed product concept out of the initial ‘sketch’ / idea. In general this design is suitable for injection moulding, but it needs to be ‘refined’. I’m trying to make an estimate on how much time this process will take an what kind of issues / problems i have to consider.


Another cost consideration is where is the tooling being made.Portugal, other EU countries or China. China tool factor in cost of repair that may happen due to low quality.

Another cost consideration is where is the tooling being made

That’s something my client will deal with. They will choose who and where the tooling will be made. Right now I am struggeling with estimating the time needed to prepare the design for production, any tips?


“but the exact design needs to be developed further and delivered to the manufacturer in a usable format.”

what is “a usable format”?

By “usable format” i mean the final design, ready to be manufatured by the injection molding company.
At this moment i have made a design that in general considers the design guidelines for injection molding, but now it needs to be developped further into a final design. The injection molding company will be closely involved in this process. During this process the initial design probably will have to be altered. I’m trying to figure out how much of my time i will spent on integrating these alterations in the initial design.


Designing plastic parts with manufacturing details is what an engineer does for a living. An engineer will consider material selection, shrinkage, tolerances, wall thicknesses, draft, sink, structure, side action/lifter requirements, part fill, gate location, ejector location, mold texture…

A really good engineer will address all of the manufacturing issues without destroying design intent.

I can quote it if you like, but I would suggest a local engineering firm.


You are not going to have a clue until you have a set of 2D orthographic design intent drawings approved.

Then you can estimate how long it will take you to do the 3D cad geometry.
Where things can get messed up is when the tool or the molder starts taking shortcuts.

One thing to reduce that is to have who makes the tool run the parts.
This way the molder can’t blame to tool maker and the tool maker can’t blame the molder.

The more you do, the greater your billings.