3D Scanner Blog

How to Prepare a 3D Inspection Program Before the Part is Available

- by David O'Connor, Manager of Technical Services, ShapeGrabber

No Part? No Problem!

You can accelerate manufacturing production by preparing your 3D inspection program in advance of actual parts being available. In fact, if you have a CAD model you have everything you need. Using the method below, your inspection program can hit the ground running.

While a CAD model is commonly used as a reference model, it can also stand in for an actual part in the design of an inspection program.	CAD Model of Part
Step 1: Using either Geomagic Qualify or Polyworks Inspector software, duplicate your CAD model and convert it into a polygon model. With a few adjustments the new polygon model is an ideal substitute for a sample part.	Polygon Model
Step 2: Increase the total number of triangles to more closely represent a scanned model. This can be achieved by refining or subdividing the triangles. Step 3: While not absolutely necessary, it is beneficial to introduce some deviations into your “sample part” to ensure that your inspection program is robust and will properly deal with real-world parts with defects. This is easily achieved by locally deforming the polygon model or simply by scaling the whole model a small amount – say, 1%.	Refined Polygons
Step 4: Once you have both original CAD data and new “sample part” data, you can follow your standard inspection programming routine. When a real first part is ready, your inspection program will be ready, too – and you’ll be able to output inspection results in minutes.	Sample Inspection Results

 

 

Inspecting Injection-Molded Plastics with a 3D Scanner

Today, injection-molded plastics are used extensively in nearly every industry, including for applications such as automotive and industrial parts, as well as consumer products. Plastics have come to replace metal and steel in many applications, and are favored for their light weight, strength, and ability to be manufactured to very complex shapes.

However, the complex, curved shapes of many injection molded plastic parts make them some of the most difficult to measure for conformance to designed dimensional specifications. For these reasons, 3D scanners are becoming increasingly popular for use in quality control and inspection processes among manufacturers of injection-molded plastic parts.

Industrial 3D laser scanners are particularly valuable for use with injection molded plastic parts because:

• They enable rigorous quality control measures to be applied to precision injection molded plastics.
• They capture millions of data points in a few minutes and represent the true surface geometry.
• They accurately measure complex shapes with compound curves and multiple features.
• They can be used to effectively detect and measure warpage, twist, bow and shrinkage, as well as to troubleshoot fit problems.
• They can scan parts of a wide range of size, material and color.

Automotives Example

Below is an example of results achieved with a ShapeGrabber 3D scanner. We scanned a complex-shaped plastic part – in this case, a radiator tank:

Image: Radiator tank scan data from ShapeGrabber, rendered in Geomagic software. Click image to enlarge.

 

 

 

 

The scan data provides millions of data points, enabling software such as Geomagic® to render a complete model of the whole part in three dimensions. The software can then be used to compare the scanned part to the CAD file to identify how well the part meets spec.

Toyota, Honda, Ogihara, Plasticos and others all use ShapeGrabber 3D scanners as part of their quality control processes.

Industrial Example

Perhaps the greatest challenge for Quality Assurance in industrial environments is the wide variety of parts that contribute to an overall product’s performance in the field.

 

Image: Injection-molded plastic part from an irrigation system.

 

 

 

Injection-molded plastic connectors (such as the irrigation system component shown here) are one example of parts that customers use 3D scanners to inspect. They come in a wide range of shapes, sizes and colours, from black to white. The connecting joints – often threaded – are typically where manufacturers need to focus their inspections.

ShapeGrabber 3D scanners excel for these applications because they are capable of very rapidly scanning parts of a wide range of sizes, shapes, rigidities, colours and materials. The resulting scans can be used to compare the part to a CAD file, or to compare a “good” part to a “bad” part to identify the nature of an unspecified flaw.

Consumer Products Example

Molded plastics are widely used in the consumer products business. From telephone handsets (shown below) to pudding cups, 3D scanners are used to ensure that objects that consumers handle are manufactured consistently to meet the company’s or the industry’s specifications.

 

Images: Telephone handset and colour-map comparison to handset CAD file. Data collected by ShapeGrabber and analysed using InnovMetric’s PolyWorks®.

Other Advantages

Using a ShapeGrabber 3D laser scanner for injection molded plastics applications also offers these advantages:

• Scans containing millions of data points can be completed within minutes, so the complete part can be verified in production.
• Scans can be easily compared directly to 3D CAD models.
• Scan data provides accurate and timely feedback on prototypes, allowing faster and better part design and process optimization.
• The visual nature of the results makes it possible to more quickly troubleshoot the source of a problem and get back to production.
• Parts do not have to placed in an expensive fixture to be scanned, leading to significant savings in capital costs.
• Scan results are documented in automatically generated reports and can be provided to customers as part of your quality assurance process.