Loose Abrasive Polishing and Honing
Lapping (Loose Abrasive Polishing) is a specialized process by which metal part surfaces are made as close to perfectly and uniformly flat as possible. Lapping can also be used to polish metal surfaces to a fine finish; with certain metals, a mirror finish can be achieved. Honing is very similar to lapping, but is used on the inner surface of a circular or cylindrical part.
Petersen Precision was founded as a lapping shop, and we’ve been an industry-leading provider of lapping services since 1966. We utilize highly effective lapping equipment that has been modified and perfected over the years to run more consistently and efficiently than most “high performance” lapping systems on the market. Our customized lapping equipment is also less expensive to operate, which translates to cost savings on your project.
Lapping and Honing Differences
Lapping is a final abrasive finishing operation that provides numerous benefits, including:
- Extreme dimensional accuracy
- Corrections of minor shape imperfections
- Refined surface finish
- Produces close fits between mating surfaces
Most lapping is done with a tooling plate or wheel (the lap) and fine-grained loose abrasive particles suspended in a viscous or liquid vehicle such as soluble oil, mineral oil or grease.
Comparatively, honing is a low-velocity abrading process that removes material at lower cutting speeds than grinding. This process produces less heat and pressure, resulting in excellent size and geometry control. The most common application of honing is on internal cylindrical surfaces. The cutting action is obtained using abrasive sticks mounted on a metal mandrel. Additionally, the fixed work does not allow for distortion through floating, clamping or chucking.
The Advantages of Micromachining Lapping and Honing
Both superfinishing lapping and honing services provide their own significant advantages. With lapping, there is no warping since the parts are not clamped and very little heat is generated. This process removes light burrs without creating new ones. Additionally, any size, diameter, and thickness from a few thousandths thick up to any height the machine will handle can be lapped.
Honing can improve all part irregularities, while creating a truly round hole, with no taper or high or low spots. Honing does not require powered machinery so there are never any chucking or locating errors within the part.
The Superfinishing Lapping and Honing Process
Lapping is the process of making a surface very, very flat. The ideal result is a part surface that is perfectly and uniformly flat across its entire surface. Lapping can allow for tolerances of 0.0005 in. to 0.00002 in. Although lapping is an abrasive process, it differs from grinding or honing because it uses a loose style abrasive instead of bonded abrasives like grinding wheels.
Petersen Precision’s superfinishing lapping and honing services involve the utilization of a large, horizontal, rotating cast-iron plate onto which multiple, independently rotating rings are placed. Workpieces are placed within these rings, with a thin layer of a slurry consisting of oil and dry abrasives. As the larger plate turns, the parts remain in place inside the rings, creating a double-rotating action on the very-fine abrasive slurry.
The pressure on the parts and the duration of the process can be finely-tuned to accommodate for the part material and the final finish required. Under perfect conditions, parts can be lapped to within 10 to 20 millionths of an inch flatness.
The microfinishing lapping and honing process allows for harder materials can be lapped to better flatness than softer materials. Similarly, harder materials can be polished to a higher finish than softer ones; only very hard materials can be lap polished to a true mirror finish.
Honing is a part finishing method that is very, very similar to lapping, but that is performed specifically on the inside diameter (I.D.) of round or cylindrical parts, or on blind- or through-holes in parts. It uses more or less the same process as lapping, and can smooth and true an I.D. to tolerances of better than ±0.0002”.
When comparing the grinding vs. honing process, within honing the material removal is accomplished at lower cutting speeds than in grinding. Therefore, heat and pressures are minimized, providing increased size and geometry control. The most common application of honing is on internal cylindrical surfaces.
Double-Sided Superfinishing Lapping and Honing Services
In addition to the “traditional” lapping process described above, we also offer double-sided lapping. Operating on the same principal as lapping, double-sided lapping works both sides of the part at once, utilizing a bonded abrasive plate, instead of a loose abrasive.
Our double-sided lapping machinery allows for much finer of thickness and parallelism of our customer’s parts. The double-sided nature of the superfinishing lapping and honing process makes it possible to achieve parallel flatness on both sides of a part. Rather than lapping one side of the part, then flipping it over to lap the other side, both sides are worked simultaneously to create high parallelism.
Contact Petersen Precision for Advanced Superfinishing Lapping and Honing Services Today
We’ve been perfecting our lapping and honing processes for more than half a century. Customers from far and wide, and in all markets, turn to Petersen Precision for precision lapping and honing services. Request a quote today, or Contact us to discuss your project.