How a better Dressing Process can improve your Grinding Performance
One of the most effective ways to improve the quality and productivity of your grinding process is to methodically assess and fine tune the method for dressing your grinding wheels. When Meister engineers are called out to help solve a customer’s grinding problem, the majority of changes they make involve dressing. We often show our customers how to make their vit bonded CBN or diamond grinding wheel sharper for more aggressive cutting or duller for a smoother surface finish, simply by adjusting the dressing parameters. Manufacturers who take advantage of these tips can:
- improve productivity by reducing cycle time and making fewer wheel changes
- save money with better wheel life
- and improve part quality with better finishes and tighter tolerances.
This article provides an overview of the dressing process and why knowledge of it is essential to achieving optimal performance and productivity in your grinding operations. It also describes the latest emerging dresser technologies and provides a calculation tool to assist in setting up a new grinding operation or troubleshooting an existing one.
Dressing 101: Contrary to popular belief, the dressing of vitrified-bonded superabrasive grinding wheels is not a black art, but a well-known scientific process, much like the grinding process itself. Dressing is also a powerful tool that engineers can use for fine-tuning their grinding process and troubleshooting grinding problems. However, before you can use this tool effectively, you need a basic understanding of the various constituents of wheel dressing.
Dressing is a combination of two processes, truing and sharpening. Truing is the procedure used to ensure that the wheel, once it has been installed on the spindle, is optimally round. it may also refer to the methods used to create shapes on grinding wheel surfaces. Sharpening involves removing bonding material from in-between the abrasive grains to expose them so they are ready to cut. For vitrified-bonded wheels these two processes occur simultaneously.
Dressing Tool Selection: Numerous tools may be used to dress grinding wheels. They include simple handheld abrasive sticks; conventional abrasive rotary wheels used on driven or brake- controlled dressing spindles; single and multipoint stationery diamond tools; and a wide variety of rotary diamond tool configurations (cups, discs, and form rollers). Rotary tools are preferred for dressing superabrasive wheels, in particular vitrified-bonded CBN and diamond wheels. See the table below for recommended dressing tools by grinding wheel type.
Dressing Variables: Once the dressing tool has been selected there are six variables that are most frequently adjusted to yield an optimal dressing and grinding process, opening a whole new world of process improvement possibilities:
- Wheel and dresser surface speeds: Linear speed at the periphery of the wheel or dresser.
- Direction at point of contact: Uni-directional (wheel/dresser turning with each other), or Counter-directional (wheel/dresser turning against each other).
- Speed ratio: The ratio of dresser surface speed divided by wheel surface speed.
- Infeed amount: The depth of cut taken per pass by the dresser on the grinding wheel.
- Traverse speed: The linear speed that the dresser travels across the wheel surface.
- Overlap ratio: The number of wheel revolutions for the dresser to traverse a distance equal to its contact width.
Dressing Calculation Tool: Once you have mastered the basics, you are ready to make some calculations. The Meister Dress Calculation Tool is specifically designed to assist the user in setting up the optimal parameters for rotary dressing of vitrified CBN and Diamond grinding wheels. It can also be used to troubleshoot problems and understand the effects of changing different variables in the dressing process. To download your own copy of the Tool, click this link to open a preview of the file and then the “download” button to save the file to your computer.
Emerging Dresser Technology: As the old saying goes; “Use the right tool for the job.” Developing promising new dresser technologies is one of the most active areas of R&D being pursued at Meister Abrasives, with the introduction of diamond dressers that excel at both truing and sharpening superabrasive wheels simultaneously. Referred to as hDD (Hybrid Diamond Dresser) and cDD (CVD-tipped Diamond Dresser), these tools rely on a unique porous hybrid-bond diamond matrix. This matrix combines the porosity of a vitrified bond with the wear resistance of a metal bond. The cumulative advantages of this technology include:
- Superior Truing (accurate and consistent profile generation on the grinding wheel)
- Superior Sharpening (does not dull the grinding wheel)
- Low dressing forces
- Grinding wheel cuts better and achieves better part quality
- Lower dress in-feed or higher skip dress possible
- Dressing tool stays sharp – No conditioning required
Learn More: If you would like to improve your dressing process and need help, don’t hesitate to contact Meister and talk with one of our experienced sales engineers.