Hand tools have a job to do, so whether we’re talking about an axe or a circular saw, functionality and durability are always the most important factors. But not all hand tools are fit for purpose, despite being the right ‘type’ on paper.
Siemens Gas & Power know this all too well. They are a leading provider of products for power generation, like gas and steam turbines and generators. They also have an extensive service network to provide maintenance and modernisation to these products. In fact, they are the only company of their type in the world that provides fully integrated products and servicing solutions across the energy chain.
In one maintenance case, their service teams use circular saws to cut into gas turbine housings to perform essential maintenance. This process requires a specially profiled tool because the turbines are contoured. Flat-plated circular saws can’t cut into the turbines in an efficient, safe or productive way.
Their original solution was to purchase the blades and outsource the production of a housing for the saw. These were made for Siemens in the Philippines to a good standard, but the assembly and production time was too high. It also wasn’t a scalable solution, with engineers having to wait 2-3 weeks for the tool.
3D printing saw housings in house
Siemens considered 3D printing as a solution to their problem after seeing how the technology could be applied successfully in other areas of manufacturing. They needed a scalable solution that would give engineers the product / tool they needed within days, and they wanted to reduce service costs in the process.
Research into the additive manufacturing market led Siemens to Markforged, who have manufactured a series of 3D printers that print nylon and composites including fibreglass, Kevlar and carbon fibre. Siemens determined they could print housings for the saw with a combination of these materials.
During the prototyping stage for the saw housing, engineers used Onyx (a specially formulated material that’s part nylon, part chopped carbon fibre) to create prototypes they could inspect and study. This process enabled them to modify the design in CAD and create a small series of dummies for review.
The production pieces were also printed in Onyx material, but they were reinforced with additional strands of carbon fibre. Models printed with this combination are stronger than 6061 aluminium with outstanding abrasion resistance.
“We bought an off-the-shelf motor and blade, but everything else was custom built,” says Siemens Gas & Power engineer Sam Dicpetris. The saw was assembled in house and tested out in the field to ensure it matched the original product. Engineers found the product to be just as good to use as the original, if not better.
Thanks to 3D printing, Siemens Gas & Power have been able to supply engineers with circular saws in just a few days versus the weeks it would take originally. They have refined their manufacturing process, eliminating their supplier in the Philippines and simplifying the process of assembly thanks to a superior housing design.
Because it’s a scalable manufacturing tool, Siemens will also realise greater value and returns the more they make. In the future, they plan to utilise the technology in other areas of the business and solve common problems out in the field.
“We can cut and make a tool that fits the exact contour of the things we’re trying to cut, which is different from anything that you can buy off the shelf,” Dicpetris says, “The carbon fibre strength is really, really impressive. When you have a plastic part that feels and looks like a plastic part, but it has this internal strength of something much different, it sets everybody up for a shock.”
To make the saw housing, Siemens used the Markforged X7. The X7 is Markforged’s top-of-the-line 3D printer, which can replace machined parts and plastic parts with a stronger and more flexible material. It has a 330mm x 250mm x 200mm build volume and in-process laser inspection, a feature which comprises a laser on the print head which scans your parts for dimensional accuracy mid-print, with a 1-micron accuracy.
Siemens has also used the Metal X to 3D print custom one-off metal parts. This enables them to manufacture custom and rare, hard-to-source legacy parts they would otherwise make with machining.
3D Printer: Markforged X7
Materials used: Onyx, Carbon Fibre. The Markforged X7 also prints Fibreglass, HSHT Fibreglass (high-strength, high-temp fibreglass) and Kevlar.
Top image credit: Siemens. Other images are credited to Markforged.