Ensuring Accuracy in Prototype Casting: Why Precision is Paramount at ACTech

Jon Cooper

When it comes to prototype casting, you only have one chance to get things right. That's why accuracy is everything here at ACTech. Discover how our partnership with GOM and cutting-edge optical measurement systems help us guarantee it throughout the entire process.

Rapid prototyping runs on a tight schedule; the mold, the first cast, the machining, and finishing touches — each step is carefully planned with deadlines that can't be missed. It's this that makes accuracy doubly important. When a millimeter or two can lead to an entire project being scrapped, getting everything right at the first attempt becomes more than a question of quality; it's the difference between failure and success.

But therein lies the challenge. Unlike serial production, which uses tools that were optimized during an intensive development process, one-off prototypes are made using 3D-printed sand mold segments and cores that are assembled by hand — a naturally less accurate technique. Despite the differences between the two, our customers require an end product that looks and functions just as well as any mass-produced part; after all, the slightest misalignment could have severe consequences for key parameters such as wall thickness.

In these cases, the margins truly are minuscule. For example, the inlets of an aluminum cylinder head must be positioned with an accuracy of 0.3 mm — roughly the size of a single grain of salt. Trying to align these pieces by eyesight alone would not be possible.

In the past, we would follow a three-step process to meet these demands. We would first manually compare 3D scans of a casting to a 3D model, make the necessary adjustments, and repeat as necessary to ensure every prototype we created was successful. It was good, sure. But it wasn't good enough for ACTech. We knew we needed to improve this process by creating something faster, more reliable, and above all, even more accurate.

GOM — a quality partner

Enter GOM — a leading provider of optical measurement software and equipment whom we've worked alongside for almost 20 years and who helped us develop the solution we needed. Today, we use high-powered 3D scanners to superimpose scan data of the assembled molded parts over the original 3D model to instantly identify any discrepancies in real-time. Each station includes large screens that clearly show our team when they have positioned the molded parts correctly.

It's a far cry from where we began, but our relationship didn't end there. We continue to provide regular feedback and advice to help develop and improve these measurement methods, using data from our own experiences.

Safe to say, this collaboration has been an undeniable success, so much so that the initial script and templates we created together are now found in a program sold worldwide. Today, it is frequently used to assess both mass-produced products and prototypes — but at ACTech, we take it even further, using GOM's solution long before and after the part is cast.

Accuracy from start to finish

Every rapid prototyping project relies on a quality mold, and absolute precision is required to create one. That's why here at ACTech, optical measurement starts at this stage. We begin with 3D models of the cores and molds, assembling everything on screen before attempting to recreate it in real life. Once the core and mold are assembled, we can scan them and superimpose that image over the 3D model. Here, we can manipulate the core in real-time to ensure it's in the right position.

Over the years, we have also identified other areas where these methods can make a real difference, including in our machining department. With the optical measurement systems in place, we can scan and calibrate the part away from the machine, saving valuable running time for every project.

To date, our teams have access to nine GOM systems throughout our facility, all used for our most complex designs — roughly 40% of all projects. These are typically cases where the mold is assembled from many separate pieces, or the wall thickness needs to be particularly thin.

Naturally, none of this would be possible without the expertise of our highly trained team members. Every day, they're tasked with building complicated 3D-printed puzzles, many of which are made up of around 20 pieces. Normally, they do so with no images or instructions to guide them and only one chance to get it right. It's their unparalleled casting expertise and understanding of the software — not to mention their skilled and steady hands — that help us provide such fantastic results.

The ACTech difference

It’s the combination of skilled employees, incredible partnerships, and a dedicated process that sets ACTech apart from others in the field. Competitors that only assess accuracy at one stage of the prototype casting process, or fail to do so at all, simply cannot offer the assurances you need when it really matters: quality; accuracy; and deadlines that won't be missed.

When you go all-in with us, you know you'll get all three.

Would you like to learn more about prototype casting or ask for more information about starting a project with ACTech? We'd love to have a conversation.


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