Part Maker Sees Big Gains in Printing Metal Fixtures, Tools and Prototypes

May 19, 2020

A provider of metal parts, Alpha Precision Group (AP) was formed in 2016 through the merger of several companies with a half-century-plus of experience in powder metallurgy. Based in St. Marys, PA, APG manufactures, via pressing and sintering, and metal injection molding (MIM), components for automotive, aerospace, defense and consumer markets.

Speed is key to APG winning and keeping jobs. 3D metal printing provides a big help here: APG engineers can significantly speed the design and manufacture of jigs, fixtures and tooling―printing parts in only days and deploying them on the manufacturing floor in less than a week. In addition, metal 3D printing, courtesy of the Studio System from Desktop Metal, offers the company far more design freedom than conventional manufacturing, according to APG officials.

Desktop-Metal-Assembly-Line-Screwdriver-ToolThis enables significant lightweighting of parts, in some cases by as much as 30 percent, resulting in less wear-and-tear on machinery and less downtime on the manufacturing floor. In addition, the technology has opened the door to designing improved workflows, particularly related to machining, which, otherwise, may be too time- and labor-intensive to pursue. A main target for those improvements: post-processing of parts in CNC machines.

And, to help earn new business, APG employs the Studio System to create prototype parts quickly for testing and design iteration. In addition, 3D printing helps APG support existing customers through production of small numbers of replacement or aftermarket parts.

The Studio System employs Desktop Metal’s Bound Metal Deposition (BMD) technology, where rods of metal powder and binders are heated and extruded to shape a part. This eliminates the loose powders and lasers employed in laser powder bed fusion, a process that necessitates a high initial investment. These factors swayed APG in its purchase decision, according to APG officials. The BMD technology enables a range of material printing, including H13 tool steel, 4140 steel, 316L stainless steel and 17-4 PH stainless steel.

Desktop-Metal-Alpha-Coining-FixtureWhen exploring the use of metal 3D printing, APG tested parts printed on the Studio System for their dimensional tolerances and metallurgical properties. Overall, APG engineers found that printed parts had tolerances comparable to traditionally manufactured parts. To evaluate material properties, APG engineers printed a number of sample parts, then halved them for examination of metal density and grain structure. Tests revealed that the printed metals showed hardness levels, density and grain structure in line with parts created via MIM.

“The Studio System is enabling us to constantly be asking ourselves how can we do this better, resulting in significant time and cost savings,” says Nate Higgins, APG business unit manager.

Asking that question has proven valuable, as success stories abound at APG.

For example, rather than requiring staff to manually tighten and loosen part fixtures, engineers designed a custom-made ratchet screwdriver tool to automate the process. Using the Studio System, they printed the tool, with its complex ratchet assembly, in only a few days from 17-4 PH stainless steel. APG officials note 93-percent cost savings and 87-percent time savings as compared to traditional manufacturing. The tool allows a single operator to run as many as five CNC machines at a time, producing a more efficient workflow and significant labor-cost savings.

Also produced through APG’s 3D printing capability, coining fixtures, which require custom geometry for each application and superior wear resistance to withstand repeated use cycles. Using the Studio System, APG printed an inhouse-designed coining fixture from 17-4 stainless steel and begin employing it in only three days. Overall, the new 3D-printed fixture offered 76-percent cost savings and 84-percent time savings as compared to traditional manufacturing.

Desktop-Metal-Thread-Checker-FixtureAnother fixture, used to push a thread-checking tool into a part, and again printed on the Studio System from 17-4 PH stainless steel, resulted in time savings of 90 percent versus traditional machining. And, APG printed the fixture for less than $100, whereas traditional machining would result in a $600 price tag.

When 3D printing these and other internal-use parts, APG found that nearly all could proceed directly to use without post-machining. For some parts destined for customers, secondary machining was necessary to ensure surface-finish or hole-size requirements.  However, APG engineers believe that they can avoid such steps by working with customers early in the design process to identify critical part features.

In addition to the cost and time savings, 3D printing has translated into an increase in manufacturing capacity. APG can turn around customer jobs more quickly while freeing capacity in its machine shop for other work.

Industry-Related Terms: Bed, CNC, Coining, Fixture, LASER, Prototype, Stainless Steel
View Glossary of Metalforming Terms


See also: Desktop Metal, Inc.

Technologies: Additive Manufacturing


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