What is Blanchard grinding?
Blanchard grinding is a form of rotary surface grinding that quickly removes material from one face of a flat workpiece by using a vertical spindle grinding wheel together with a rotating magnetic chuck. Also known as rotary surface grinding, this technique was developed by the Blanchard Machine Company in the early 1900s and soon became valued for efficiently finishing large, flat surfaces.
How Does Blanchard Grinding Work?
Blanchard grinding is performed by mounting the workpiece on a turntable (typically using a magnetic chuck for ferrous metals, or mechanical/vacuum fixtures for non-magnetic materials) and lowering a vertically oriented grinding wheel onto the surface. The work table rotates (commonly in a counter-clockwise direction) while the grinding wheel turns in the opposite direction, grinding the part from above. That opposing motion produces the distinctive crisscross pattern on the ground surface.
Because the wheel makes broad-area contact and substantial pressure can be applied, the process often removes a large amount of stock in a single pass. The Blanchard grinding process yields a flat, uniformly ground surface on the workpiece, and the characteristic cross-hatch marks are a clear visual indicator of an authentic Blanchard grind.
Advantages of Blanchard Grinding
1. Fast Material Removal
Blanchard grinding is noted for its high stock-removal capacity, able to strip significant material quickly. This makes it especially efficient for reducing thick components to a target thickness or for flattening warped plates.
2. Large Part Capability
Blanchard grinders are available in very large sizes, enabling grinding of parts that may not fit on other machines. The rotary table can accommodate parts several feet across, and high-horsepower spindles can take heavy cuts-ideal for large, flat items such as machine bases, plate stock, die blocks, and fabrications.
3. Cost-Effective for Big Jobs
Due to rapid stock removal and the ability to process large pieces (or multiple smaller parts simultaneously), Blanchard grinding is often more economical than precision surface grinding for large workpieces. Fewer passes are required to reach the desired flatness, reducing machining time and cost for sizeable parts.
4. Uniform Flatness
The rotary action of the Blanchard process promotes uniform flatness across the entire part. The combination of a wide grinding wheel and a continuously rotating table helps eliminate localized high spots, allowing even large steel plate sections to be ground flat and parallel within close tolerances.
5. Characteristic Surface Finish
Many users value the distinctive cross-hatched surface left by a Blanchard grinder. In some applications, this swirling matte finish is both functionally useful and aesthetically uniform.
