Before a new injection molded part moves into production, we need to answer a basic question: does what’s coming out of the mold match the customer’s drawing?
At Lewis Plastics, inspection starts with the first articles and continues as production gets underway. Our quality team performs dimensional inspection in a climate-controlled quality lab, using different measurement methods based on the part and its requirements. FAI, ISIR, and PPAP documentation are also supported when the project calls for them.
Our 3D scanner provides another way to evaluate molded geometry. Instead of relying only on measurements taken at individual locations, we can capture the part’s geometry and compare it with the digital model. It’s useful for initial validation, but it can also help us spot changes during production and narrow down areas that may need a closer look.
For a procurement specialist, the question behind all of this is pretty straightforward: how will your injection molding supplier catch a problem before the parts arrive at your facility?
What Happens When the First Articles Come Off the Press?
The first articles give us an actual molded part to compare with the print. From here, the quality team begins checking the dimensions and features the customer has specified.
Some measurements are relatively simple. Hole locations, overall dimensions, or other defined features may be checked using conventional dimensional inspection equipment. Parts with contours or harder-to-reach features may need a different method.
Our quality lab includes a Coordinate Measuring Machine (CMM), Video Measuring Machine (VMM), optical comparator, and non-contact systems. Full dimensional layouts are available for ISIR, PPAP, and FAI requirements.
First article measurements are useful later, too. Once we know where an approved part falls within its specifications, we have a reference when production continues. If a dimension begins moving from where it started, the quality team can compare the new measurements with the earlier data and start looking into what changed.
Procurement teams don’t have to rely on a visual check or a press setup as proof that the part meets the print—there’s documented inspection behind the approval.
What Does the 3D Scanner Add?
Individual measurements tell us a lot, but they don’t always tell the whole story of what’s happening across a molded surface.
Our 3D scanner captures the geometry of a part and allows the quality team to verify it against the digital model. We added the scanner to support faster, more detailed dimensional inspection, particularly for close-tolerance molded components.
Imagine an area of a part beginning to shift slightly during production. Checking a few specific dimensions may tell us where those individual points fall, while a scan lets us look at the surrounding geometry as well. We get a better idea of how much of the part is involved and where the change is occurring.
Non-contact inspection is also useful for geometry that isn’t well suited to being physically probed. Depending on what we’re checking, optical measurement or 3D scanning may give the quality team information that would be difficult to collect another way.
The 3D scanner does not replace the CMM or the other inspection equipment in the lab with a scanner; each tool has a place. The part, print, and feature being evaluated help determine which method makes the most sense.
How Do We Decide Which Quality Inspection Method to Use?
If you walked into our quality lab, you’d find several ways to measure a molded component. We don’t send every part to the same machine and run the same inspection routine.
A defined dimensional feature may be a good fit for the CMM. Optical measurement makes sense for features better inspected without physical contact. When we need to understand the shape of a larger surface or compare molded geometry with a digital model, the 3D scanner gives us another option.
The inspection environment matters as well. Our lab is climate controlled, which helps limit outside variables when measurements taken at different stages of a project need to be compared.
Equipment only gets you so far, though. Someone still needs to understand the drawing, select the appropriate measurement method, and recognize when the data calls for another look. Once production is running, those decisions become part of monitoring the process over time.
What Are We Looking for During Production?
Lewis uses in-process inspection and Statistical Process Control (SPC) to follow dimensional performance while production is running. Real-time data collection helps our team recognize changes during the run rather than waiting until production is finished.
Consider a dimension that was comfortably within tolerance when the first articles were approved. Later measurements may still meet the print, but perhaps they’re beginning to move consistently in one direction. We’d rather investigate the movement at that point than wait until the dimension crosses the tolerance limit.
The 3D scanner becomes useful here when one measurement doesn’t fully explain what we’re seeing. We can compare the molded geometry with the model and get a broader look at the affected area.
For procurement, catching the shift during production gives the molding and quality teams time to investigate and resolve before parts are completed, packed, and shipped.
Can a 3D Scan Help Identify Tooling Maintenance Needs?
Molds see repeated cycles throughout production, so wear and maintenance are part of their working life. Sometimes a change in the molded part is an early clue that an area of the tool deserves attention.
Let’s say repeated inspections keep showing a dimensional change in the same location. With the 3D scanner, our team can get a closer look at the geometry around that location and compare it with the model. If the difference continues to appear, we have a specific area to investigate instead of starting from scratch.
From there, the team can review what’s happening in the molding process and take a closer look at the tool if needed. Lewis has in-house tooling capabilities for mold maintenance and repair, so our tooling team can get involved when inspection data points in that direction.
The scanner isn’t going to tell us, “This mold needs maintenance.” What it does is show us where the molded geometry is changing. Having that information earlier gives our team a chance to investigate before the change progresses far enough to produce nonconforming parts or disrupt a delivery.
What Should Procurement Look for in an Injection Molding Inspection Process?
When you’re evaluating an injection molding supplier, take a look beyond the equipment list. Ask what happens when the first parts come off the press. Find out how inspection continues after approval and what the supplier does when measurements begin to change.
At Lewis Plastics, our ISO 9001:2015 quality system supports inspection before and during production. The quality lab gives our team several measurement options, and the 3D scanner expands what we’re able to see when a part needs a closer geometric comparison.
If something starts moving, we want to catch it while the run is still active. A closer look might confirm the process is behaving as expected, or it may send us back to a specific area of the mold for further review. Either way, we have information to work with before the parts reach the customer.
Have a molded part with tight dimensional requirements? Contact Lewis Plastics to talk through your project and the inspection approach that makes sense for it.