Rotary Grinders Leave Cleaner Build Plates

Metal additive manufacturing removes many bottlenecks from the manufacturing process, but it also introduces a notable new one: users must remove all residual metal from build plates before reusing them. The latest rotary grinders can provide an efficient alternative to wire EDM or bandsaws for removing this material while also ensuring flatness and levelness. These machines put the tight tolerances, quality surface finish and automation-driven efficiency that build plate grinding demands well within reach.

Automate Inconsistencies Away

“Unlike older-style machines, advanced rotary grinders do not need constant operator input or oversight,” says Doug Hedges, chief technology officer of AM contract manufacturer Beehive3D, Inc. “This allows the operator to multitask and minimizes the risk of error.”

For example, high-end rotary surface grinders can control the initial contact between the abrasive wheel and the build plate instead of leaving it to the operator. They use vibration feedback from sensors to automatically fine-tune not only the pressure of the spindle motor, but also how quickly it moves the wheel down onto the build plate. The grind cycle begins when the machine senses that the abrasive wheel has contacted the build plate.

“Different grind recipes can be set for different customers, material types or construction builds so complex programming or data does not need to be entered at the start of each job,” explains Erik Lawson, engineering manager at DCM Tech.

Also important is the ability to alter grinding parameters through the grind cycle. The material characteristics of the printed part residue and the build plate may be very different, and the grinding abrasive must work differently on both surfaces. Modern rotary grinders automatically make that transition. Newer equipment also tends to include built-in load monitoring, reducing the necessary amount of operator oversight.

Automatic wheel dressing is another example of grinding automation. Manual dressing is a labor-intensive process that typically requires holding a tool against the wheel to knock off used or clogged abrasive. Hard part materials like Inconel can require dressing wheels as often as every 10 minutes — Hedges particularly recommends automatic wheel dressing for applications using these materials.

Simple Controls and Recipes

Some high-end rotary grinders, such as DCM Tech’s IG series, offer simple controls such as a touchscreen Human Machine Interface (HMI) that operators can use to enter requirements or necessary adjustments without programming. This capability supports processing flexibility by making it easy to adjust grinding factors to prevent issues from reoccurring.

For routine processes, the IG series can use grind “recipes” with sets of parameters for different AM construction builds to further speed production, enhance quality and aid in quick changeover.

“Different grind recipes can be set for different customers, material types or construction builds so complex programming or data does not need to be entered at the start of each job,” explains Erik Lawson, engineering manager at DCM Tech. “A new recipe can be created for job variations, such as a different finish for a specific AM material.”

These recipes can accommodate build plate texture requirements, eliminating the need to “roughen up” a build plate in a separate process so the AM part will properly adhere to the surface during buildout. Instead, Hedges says, operators will only need to wipe down the build plate with alcohol or another solvent and let it dry before using it again.