Q&A on Injection Molding

Injection Molding & Mold Making: FAQs

This FAQ is to help you understand the information and process to get a quote and start an injection molding project.

Part & Project Information

1. What technical information is required about the plastic parts to get a quote?

To give you the most accurate and timely quote, we need all the information about your plastic part. Key details are:

  • 3D CAD Files: These are a must. See question 4 for preferred formats.
  • Material Specifications:
    • Resin Type: (e.g., ABS, Polypropylene (PP), Polycarbonate (PC), Nylon (PA66), HDPE, etc.)
    • Specific Grade: If known (e.g., PC Lexan 141R).
    • Additives: Colorant (Pantone, RAL number, or sample), UV inhibitors, flame retardants, fillers (e.g., glass fiber), etc.
  • Detailed Dimensions & Tolerances:
    • Overall part dimensions.
    • Critical dimensions and their tolerances. If you have 2D drawings with GD&T (Geometric Dimensioning and Tolerancing), please provide them.
  • Production Volume:
    • Estimated Annual Usage (EAU): How many parts do you need per year?
    • Initial Order Quantity (EOQ): How many parts for the first production run?
    • Projected Lifetime Volume: Total parts over the life of the product. (This helps us determine mold cavitation, mold material and overall project feasibility.)
  • Application/End-Use of the Part:
    • What is the part used for? (e.g., consumer electronics housing, automotive component, medical device).
    • What are the functional requirements? (e.g., load-bearing, flexibility, impact resistance).
    • What environment will it be exposed to? (e.g., temperature extremes, chemicals, outdoor use).
  • Cosmetic Requirements:
    • Are there any aesthetic requirements?
    • Which surfaces are cosmetic?
    • Any specific requirements for gate marks, ejector pin marks or parting lines?
  • Sample Parts (if available): If you have existing samples, even if they are not perfect, they can be very helpful.

**2. What are the specifications of the injection molding machine?**We will usually determine the right injection molding machine for your part and production requirements as your molding partner. However, if you:

  • Have an existing mold you want us to run, or
  • Plan to run the mold at your own facility or a third-party facility, then the following machine specifications are important:
  • Clamping Force (Tonnage): The force required to keep the mold closed during injection.
  • Shot Size / Injection Volume: The maximum amount of plastic the machine can inject in one cycle. This must be enough for your part volume plus the runner system.
  • Mold Space / Platen Dimensions:
    • Tie bar distance.
    • Maximum and minimum mold height.
    • Maximum daylight (opening).
  • Ejector Stroke and Pattern: The distance and configuration of the machine’s ejector system.
  • Nozzle Radius and Sprue Bushing Compatibility.

If you don’t have this information, we can usually determine the machine size based on your part data.

plastic mold structure

3. What else do we need for a quote?

Beyond the basic part information, these details help refine the quote and ensure the final product meets your expectations:

  • Tolerances: Specify any critical dimensional tolerances. Standard industry tolerances will be applied unless otherwise specified.
  • Surface Finish:
    • Specify required surface finishes using SPI (Society of the Plastics Industry) standards (e.g., SPI A-2 for high polish, SPI B-1 for semi-gloss, SPI C-2 for matte, SPI D-3 for textured).
    • If a specific texture is needed, provide the Mold-Tech (or equivalent) texture designation (e.g., MT-11010).
  • Runner System Preference (if any):
    • Hot Runner: Generally preferred for high-volume production, faster cycle times and eliminating runner scrap. Molds are typically more expensive.
    • Cold Runner: Simpler and less expensive molds, but results in runner scrap and can have longer cycle times. (We can advise on the best system for your project if you don’t have a preference.)
  • Gate Type and Location:
    • Do you have any preferences or restrictions on the type of gate (e.g., tab gate, sub gate, pin gate, cashew gate) or its location on the part? Cosmetic or functional requirements often dictate this.
  • **Color Requirements:**4. What design file formats do you prefer?

To ensure compatibility and accuracy in mold design and manufacturing, we prefer the following 3D CAD file formats:

  • Most Preferred:
    • STEP (.stp, .step): This is the most robust and neutral format that accurately represents solid geometry.
  • Also Acceptable:
    • Parasolid (.x_t, .x_b): Another solid modeling kernel format.
    • IGES (.igs, .iges): An older neutral format; ensure it’s exported as a solid model if possible.
    • Native CAD Files: Files from software like SolidWorks (.sldprt), Creo/ProE (.prt), CATIA (.CATPart) can be acceptable, but please check with us first.
  • Less Ideal / For Reference Only:
    • STL (.stl): This is a mesh format primarily used for 3D printing. It approximates surfaces with triangles and is not ideal for precision mold manufacturing. It can be used for initial visualization or quoting simple parts, but a solid model will be required for mold design.
  • **2D Drawings:**2D Drawings:
  • In addition to 3D files, 2D drawings (e.g., .pdf, .dwg, .dxf) showing critical dimensions, tolerances, material specifications, surface finishes and other annotations are highly recommended and very helpful.

Please export your 3D files as “solid models” rather than “surface models” whenever possible.

5. Do you offer design or prototyping services if CAD files are not available?

Yes, many molders, including us, offer services to support clients who may not have complete CAD files or who are in the early stages of product development:

  • Design for Manufacturability (DFM) Analysis: Even if you have CAD files, we typically perform a DFM analysis to identify potential molding issues and suggest design modifications to optimize for cost, quality and production efficiency.
  • Part Design Services: If you have a concept, sketch, existing physical sample or basic drawings, we may be able to assist in developing a fully detailed 3D CAD model suitable for injection molding. Please contact us to discuss your specific needs.
  • Prototyping Services: We can offer various prototyping options to help you validate your design before committing to production tooling:
    • 3D Printing (SLA, SLS, FDM): Good for quick form, fit and basic functional checks.
    • CNC Machined Prototypes: Can be made from production-intent or similar materials for more robust testing.
    • Soft Tooling / Prototype Molds: Often made from aluminum or P20 steel, these molds are less expensive than full production tools and are suitable for producing a limited number of parts (typically a few hundred to a few thousand) in the actual production material. This is an excellent way to test functionality and market acceptance.

Please check with us for availability and scope of these services.

Logistics & Timelines

6. Do you need information about the mold’s destination for logistics purposes?

Yes, please. We need to know the destination for several reasons:

  • If we are manufacturing the mold AND producing the parts for you: We need the final destination of the parts to calculate shipping costs and arrange logistics.
  • If we are only manufacturing the mold, and it will be shipped to your facility or another molder for production: We need the final destination of the mold to:* Provide shipping quotes (freight, insurance).
  • Determine crating and packaging requirements for transport.
  • Manage import/export documentation and customs procedures if the mold is being shipped internationally.
  • Coordinate delivery schedules.

Please provide the full shipping address for the mold.

7. How long does it take to get a quote?

The time to provide a quote can vary depending on:

  • Part and Mold Complexity: Simpler parts and molds can be quoted faster than complex ones with undercuts, multiple mechanisms, etc.
  • Information Provided: The more information you provide (as outlined above), the faster and more accurate the quote. Missing information will delay the process as we will need to follow up.
  • Our Current Workload: Like any business, our quoting time can be affected by the volume of requests we are handling.
  • DFM Analysis: If a preliminary DFM analysis is required to identify potential issues or suggest design modifications before quoting, this will add to the timeline.

General Timelines (Estimates):

  • For simple parts with complete information: 24 to 72 hours.
  • For complex parts or projects requiring analysis: 3 to 10 business days.

We will always try to get quotes back to you as quickly as possible without compromising accuracy. If you have a rush request, please let us know and we will do our best to accommodate your timeline.

Hope this helps with your injection molding projects. Contact us if you have any other questions.