Injection Molding Quality Control and Standards
How we use digital processes, scientific molding, and inspection reporting to manufacture quality parts consistently
- Manufacturing analysis
- Scientific molding and process qualification
- Critical to quality reporting
- GD&T specifications
Certifications
ISO 9001:2015 | ITAR Registered
Producing high-quality molded parts consistently requires a combination of in-process inspections and controls and dimensional verification after production. Designing a part with the manufacturing process in mind is the first step in ensuring a quality molded part. That’s why we provide design analysis with every injection molding quote. Getting manufacturing analysis early in the molding process can help eliminate costly redesigns, save development time, and take the guess work out of the molding process. Before placing an order, you’ll know if your design requires any changes, get recommendations to improve its moldability, and see other useful information to understand how the final part will be molded.
Design for Manufacturing (DFM) Analysis
When requesting a quote through our online quoting system, you will receive manufacturing analysis and pricing. The first step in the digital manufacturing process can enable customers to test multiple designs simultaneously, thereby arriving to design validation sooner, which saves time in the development cycle.
How our manufacturing analysis can improve quality of injection-molded parts:
- Identifies thick walls
- Identifies features with insufficient draft
- Mold flow analysis
- Select gate location
- Select ejector pin location
Design Support from Injection Molding Experts
Consultative Design Services: Work directly with an injection molding applications engineer to improve the moldability of your design. Think of it like having your very own injection molding consultant on your team. During this process, our applications engineer will collaborate with you to understand your design goals, review the manufacturing analysis provided in your online quote, and make changes to the 3D CAD file.
Protolabs Proposed Revision (PPR): In some instances, we can provide a second CAD model to you—called a Protolabs Proposed Revision (PPR). This is a new CAD file with changes already made. The revised model can be used immediately or you can transfer the modifications to the original model. Following the DFM analysis, and, in some cases, the PPR, once the part has been approved, Protolabs moves into the final step before actual production—the digital preparation.
Scientific Molding: Consistently Delivering Quality Parts
We use scientific, or decoupled injection molding process to manufacture consistent, repeatable parts for our injection molding customers. We develop, optimize, and document the ideal set up process for each injection molding project so that the same process and parameters are followed for every single run of a customer's mold. Any modifications are documented to provide traceability across molding runs.
Whether the part will be run again or on a different injection molding press, or if it will be ordered once several months later, scientific molding ensures part-to-part and run-to-run consistency by documenting the exact process used to set up the tool in order to meet the particular resin needs and dimensional requirements.
By following these industry best practices we can ensure that each part has the same properties as the previous part, by controlling fill, pack, and hold. This results in two key benefits for our customers: more consistent parts that are higher quality and inspection reports for qualification.
Injection Molding Quality Control
As part of the Protolabs standard, we measure up to four plane-to-plane and outside diameter dimensions based on your CAD model (X, Y, Z) to quoted tolerances. We automatically define these quality control checks and perform the measurements on a sampling of parts.
In addition, we provide a wide range of other quality documentation. Compare the benefits of each inspection report to see which is best suited for your project needs.
Critical to Quality (CTQ)
CTQ Partial FAI (First Article Inspection)
Benefits: Includes a 3-part dimensional first article inspection of 5 critical features
Measurements: Up to 5 plane-to-plane, hole-to-hole, ID/OD, or radii measurements as critical features
Additional Features: Formatted report with bubbled part image and result summary chart
Eligibility: On-demand manufacturing, injection molding orders. Can be added to any other order.*
Additional Lead Time: None
Sample Plan: After the molding process is established, a partial FAI is completed on the first three parts off the tool
Additional Information: Available to select in "Secondary Operations" during checkout. Upload a 2D drawing with critical features identified. Contact us with questions.
* Excludes: Thermoplastic elastomers (TPU, TPV, TPO, etc.) and Liquid Silicone Rubber (LSR).
CTQ DIR with Capability Study
Benefits: Includes a 30-part dimensional capability study of 5 critical features
Measurements: Up to 5 plane-to-plane, hole-to-hole, ID/OD, or radii measurements as critical features
Additional Features: Formatted report with bubbled part image and result summary chart
Eligibility: On-demand manufacturing, injection molding orders. Can be added to any other order.*
Additional Lead Time: None
Sample Plan: After the molding process is established, a 30-piece capability report is based on a group of parts that is chosen from an evenly distributed sample
Additional Information: Available to select in "Secondary Operations" during checkout. Upload a 2D drawing with critical features identified. Contact us with questions.
* Excludes: Thermoplastic elastomers (TPU, TPV, TPO, etc.) and Liquid Silicone Rubber (LSR).
Additional Inspection Reports
Digital Inspection Report / Full FAI
Benefits: Verifies numerous critical dimensional specifications
Measurements: Up to 50 measurements: ID/OD, plane-to-plane, hole location, and angles
Additional Features: Options include a 360-degree, 8+- position 3D scanner collects data, identifies dimensional variance, and create a visual aid and color map for a direct CAD-to-scan comparison
Eligibility: On-demand manufacturing, injection molding orders
Additional Lead Time: Quoted at time or order, typically 6+ business days
Sample Plan: Random selection during the molding operation based on requested quantity specified
Additional Information: Available to select in "Secondary Operations" during checkout. Contact us with questions.
Production Part Approval Process (PPAP)
Benefits: Verifies that a production process can reliably produce
Measurements: Nineteen components that range from customer approval to sample part production
Additional Features: Level 3 PPAP document is provided in PDF format for requested manufacturing orders
Eligibility: All injection molding orders
Additional Lead Time: Quoted at time or order, typically 11+ business days
Sample Plan: Random selection during the molding operation based on requested quantity specified
Additional Information: Available to select in "Secondary Operations" during checkout. Contact us with questions.
How are Part Dimensions Measured?
We use industry standard coordinate-measuring machines (CMM)—calipers and pin guages—just as you would expect from an industry leading manufacturing partner. What differentiates our process is that we’ve applied patented automation technology to our CMMs to enable in-process inspection with no additional cost or lead time.
Parts are measured at an equidistant cadence of n/30 where n = total part order quantity. Along with the measurement data from each part, the Capability Report will also provide the average measurement, standard deviation, and a Process Capability Index (Cpk) value for all critical dimensions.
Additional Quality Capabilities
Medical Molding Capabilities
We do offer ISO 13485 injection molding capabilities through trusted partners.
