August 9, 2020Providing the Missing Link in Hot Stamping Rework See the article
At the beginning of a manufacturing process, a mold, dye, or jig is engineered according to the theoretical CAD model. The aim of this tooling, made precisely from the nominal model, is to produce parts that correspond to the technical requirements. It turns out, however, that there are often differences between the theoretical model and the reality of an industrial environment. Different phenomena interfere with the tooling, causing problems and imperfections on the parts. Adjustments and iterations, therefore, are required to ensure that the tools and molds, even if they correspond exactly to their nominal models, produce good parts that meet quality controls and customer demands.
Challenges: Non-Predictable Phenomena
The reality of an industrial environment differs from the theory illustrated in CAD models. During the manufacturing process, several phenomena that are difficult to predict can occur. Spring backs when stamping a dye, shrinkage when building a mold made of composite material, or thermal forces when welding two elements together are all good examples of phenomena that impact tooling precision. Nevertheless, modeling the removal of a composite resin, the spring back of a dye, the impact of a weld remains difficult, complex, and expensive.
Initially, the tooling is built according to the theoretical model, which is developed to create manufactured parts that meet the production requirements. But, in the reality of the industry, the aforementioned phenomena interfere with the molded or stamped parts. As a result, the parts do not meet the technical demands and must be adjusted, corrected, and altered in order to pass the quality controls.
Starting with nominal models is, of course, a good first step, but let’s not forget that what manufacturers want is not so much a perfect tooling, but good parts that meet technical requirements and customer needs.
Solution: Iterative process
When unpredictable phenomena alter manufactured parts, an iterative process of quality control starts. The most commonly used method is to work on the part before adjusting the tooling. More precisely, this method involves producing a part, measuring it, and analyzing deviations between the part and the CAD model. Hence, if we notice that there are some missing (or extra) mms in one place, we will go to the corresponding surface on the mold, dye, or jig in order to grind or add material. Thus, the iteration is performed on the tooling after measuring the manufactured part.
Once this operation completed, we restart the manufacturing process in order to produce a new part that will be measured to verify if there are any remaining deviations. This iterative process will continue on a loop until we obtain the desired part (i.e., when the manufactured part corresponds to its CAD model).
This iterative process of quality control requires a fast measuring tool in order to produce the next part without delay. In addition, the measurement technology must have the capability to be used directly on the shop floor and the capacity to measure all types of sizes, surface finishes, and geometries. 3D scanning technology, with its speed, portability, and versatility, enables production teams to make the required corrections to the tooling quickly and effectively.
Benefit: CMM Report
The customer who buys the manufactured parts may require a CMM report from the tooling manufacturers. Thus, a second measurement tool that will reduce the CMM workflow is an important benefit for manufacturing companies. With a portable 3D scanner, they can measure the majority of the entities and multiply the intermediate inspections, preserving the CMM for the final inspection and report generation.
Benefit: Reverse Engineering
Once we have a tooling for which the CMM has certified the manufactured parts, the mold, dye, or jig can be scanned for reverse engineering. Thus, if the tooling wears out and a new one is required, we will not use the nominal model for the next manufacturing process. Instead, we can work directly from the model that we know builds good parts. All initial iteration time is saved for future productions.
Benefit: Periodic Quality Control
Instead of measuring a part out of 50 or 100 with the CMM, 3D scanning technology enables the possibility of conducting periodic quality controls. Indeed, a portable 3D scanner is beneficial for the mold and tool industry because it increases inspection sampling and saves time by measuring parts directly on the floor of production without having to bring them to the CMM. Thus, periodic quality controls ensure that the production remains in control and delivers parts on time.
Benefit: Quality Assurance
If the manufactured parts suddenly do not match the technical requirements, the manufacturing company will fall into an investigation mode, which will cause a lot of stress and uncertainty. With a portable 3D scanner, quality assurance will be able to intervene without further delays and find the root cause by acquiring a lot of data quickly and investigating directly on the shop floor.
Several phenomena specific to an industrial environment regularly occur on the production floor. They cause unexpected spring backs or shrinkage. Necessary adjustments are required to ensure that the tooling, even if it exactly matches its nominal model, produces good parts that meet quality controls and customer requirements. These iterations are facilitated by 3D scanning, which, due to its speed, portability, and versatility, is an effective alternative to the CMM that can remain free for final inspections. In addition, 3D scanning offers the possibility of reverse engineering the tooling that produces the good parts, performing periodic quality controls, and quickly resolving unexpected issues that may occur at any time.