Recreating Legacy Parts: Breathing New Life Into Automotive Parts

While additive manufacturing and classic automobile restoration may seem an unlikely combination, being able to recreate legacy parts make a compelling case to adopt the technology. By Jennifer Costa, communications consultant, and Linda Crum, technical writer, ExOne.

Restoring classic cars comes with a unique set of challenges, especially in terms of rare and limited release cars. Legacy parts can be difficult to find and costly. Paul Vorbach and his partner Bill Hahn of Hahn-Vorbach & Associates decided that a different approach was needed to offer his customers cost-effective solutions.

Hard-to-find legacy parts for automobiles can be created using additive manufacturing.

In 2015, Mr Vorbach explored ways that additive manufacturing could support producing hard-to-find legacy parts. With manufacturing technology company ExOne being able to provide what they needed, while reducing turnaround time and increasing availability while providing customisable parts, Mr Vorbach and Mr Hahn developed HV3D Works to offer their customers more options by using additive manufacturing technology to restore and customise cars.

They were able to utilise scanning and CAD software to recreate impossible-to-find legacy parts and then, print the parts directly using the company’s binder jetting metal process. Today, the company is one of only a handful of companies to integrate additive manufacturing in the car restoration industry.

Binder Jetting Process

Binder jetting is an additive manufacturing process in which a liquid binding agent is selectively deposited to join powder particles. Layers of material are then bonded to form an object. The print head drops binder into the powder. The job box lowers and another layer of powder is then spread and binder is added. Over time, the part develops through the layering of powder and binder.

Powders

The process is compatible with several types of powders which allow customers to use powders that fit their process.

Powder Dispensing And Spreading

Powder is held in a hopper on the machine in order to be dispensed throughout the printing process. A counter-rotating roller is then used to compact and level the surface, leaving a smooth surface for printing.

Binder Jetting

After spreading the powder, binder material is deposited onto the print bed using the print head. Dispensing between 450 and 900 drops per inch, the print head traverses the bed to dispense binder only in the desired areas. The binder jetting process has proprietary binders that are designed for certain powders and applications.

Curing Process

Depending on the binder, the 3D printed parts are cured. The build box is placed in an industrial curing oven at around 200 deg C for two to 12 hours. The curing process strengthens the binder, allowing the part to be handled.

De-Powdering

During the de-powdering process, a vacuum is used to remove bulk powder and air is used to clear fine features on the part. The unprinted powder that is removed from the build box is then sieved and returned to the machine for future production runs, resulting in the recyclability of powder.

Sintering

Parts produced with the binder jetting process can be sintered or infiltrated depending on the material printed or the desired material properties using an industry standard furnace. The infiltration process results in the porosity of the part being filled with bronze due to capillary action. Parts that are sintered shrink as the powder particles are bonded together, producing a highly dense part.

Finishing

After completing the sintering process, parts can be machined, coated or blasted to attain desired finishes.

Enabling Business

The technology enabled Mr Vorbach to reimagine his business model. His company is now a niche business that is addressing a growing challenge facing Hahn-Vorbach and the industry at large: the costliness of quality parts and the rarity or unavailability of parts.

“It was our search for rare parts that initially led us to examine and explore the possibilities of additive manufacturing,” explains Mr Vorbach. “I recognised the potential of what we could do for the restoration business if we had the ability to access more of the parts we needed using additive manufacturing.”

Unique Position

Binder jetting is an additive manufacturing process in which a liquid binding agent is selectively deposited to join powder particles.

Considering that the automotive specialty equipment market was valued at more than US$39 billion in 2016, according to the Specialty Equipment Market Association, the company is uniquely positioned with their services that include 3D scanning, reverse engineering, custom part design, and 3D print management.

The binder jetting technology offers distinct advantages over traditional methods, being able to create the complex geometries of automotive parts, with ease. In addition, the process can lower cost and shorten the often lengthy turnaround time for legacy parts.

Mr Vorbach is working to increase his offerings to include more materials and greater variety options in customisation.

APMEN Fast Fab