By Scott Kraemer, Tooling Engineer and Mantle Senior Application Engineer
Mantle’s TrueShape™ process produces 3D printed metal parts with a surface finish of 1-3 μm Ra, which is comparable to that obtained from CNC machining or electrical-discharge machining (EDM). Because there are often cases where toolmakers need to modify a mold/die or its components – because of customer-requested engineering changes, to cut new features, or to make repairs to a worn component – it’s important to understand things like how a 3D printed tool component from Mantle’s technology behaves when welded or EDM’d.
To better understand this, we enlisted the help of several toolmakers to perform EDM and welding operations on printed and sintered blocks of Mantle’s P2X material. They found it performs just like the standard P20 material with which the tooling industry is familiar.
SINKER & WIRE EDM
Both sinker and wire EDM operations were performed on conventional P20 and Mantle P2X steel using the same operating parameters. The two materials performed nearly identically except for a couple of exceptions noted below:
- In sinker EDM, when a copper electrode was used with P2X, some minor pitting was observed. To avoid this problem, we recommend using graphite (POCO 3) electrodes.
- In wire EDM, no wire breakage was observed when running P2X. When running standard P20 steel, it’s common to have wires break, which creates downtime and hurts productivity.
- In both operations, a similar surface finish was achieved vs. conventional steel.
In this example, Fathom printed a few features slightly oversized because the features were too small to be printed and then used sinker EDM to
achieve their final geometry.
| EDM Operation | Variables | Mantle Printed P2X | Mantle Printed H13 |
| Sinker EDM | Graphite (POCO 3) electrode | Equivalent | N/A |
| Copper electrode | Equivalent but with minor pitting | Equivalent | |
| Feed | Equivalent | Equivalent | |
| Overburn | Slightly less than P20 | Equivalent | |
| Wire EDM | Amperage | Equivalent | Equivalent |
| Wire diameter | 0.010 inches / 0.25 millimeters | 0.010 inches / 0.25 millimeters | |
| Wire breakage | None | None | |
| Feeds & speeds | Equivalent | Equivalent |
WELDING
To compare the weldability of P2X vs. P20 steel, two different operations were performed: laser welding and TIG (tungsten inert gas) welding with a 420 filler rod. The same process settings were used in each operation for both materials. As with standard P20, the local weld area was slightly harder than the surrounding metal. For all intents and purposes, the two materials behaved exactly the same in both welding operations.
| Welding Operation | Mantle P2X Performance vs. Conventional P20 Steel |
| Laser | Equivalent |
| TIG (420 filler rod) | Equivalent |
FOR THE BEST EDM AND WELDING PERFORMANCE WITH MANTLE’S P2X MATERIAL
- When burning with a sinker EDM, use a graphite (POCO 3) rather than copper electrode.
- When burning with a wire EDM, expect to break wires less frequently than with P20, which should improve uptime.
- As when welding P20, expect the weld area to be harder than surrounding material.
ABOUT SCOTT:
Scott Kraemer is a Senior Application Engineer at Mantle and is a director on the board of the SPE Mold Technologies Division. He is passionate about toolmaking and has spent his career as a mold designer, tooling engineer, and injection molding specialist at companies like Innatech, L&L Products, and PTI Engineered Plastics. For the last 8 years, Scott has been at the forefront of applying 3D printing to the tooling industry and has worked with many leading metal and polymer 3D printers.
