Grinding is generally divided into coarse grinding and fine grinding, while polishing is divided into coarse polishing and fine polishing.
In many cases, we adopt a three-step process to achieve the desired surface quality:
Coarse grinding
Fine grinding
Fine polishing
With these three stages, the workpiece surface can achieve excellent flatness, parallelism, and roughness.
For customers with less demanding requirements, two steps (coarse grinding and fine grinding) may be sufficient. The exact process always depends on the initial condition of the workpiece and the quality standards set by the customer.
Although grinding and polishing can be performed on the same flat polishing machine, the configurations are different:
Grinding requires grinding plates and grinding liquid.
Polishing requires polishing plates, polishing pads, polishing cloths, polishing wheels, and polishing liquid.
When switching from grinding to polishing on the same machine, operators need to replace the plates, liquids, and other accessories accordingly.
Grinding plates are usually made by casting various metallic powders with specific toughness and brittleness, giving them strong cutting ability for rapid surface finishing.
Common materials include tungsten steel, alumina, cerium oxide, synthetic iron, and copper, selected according to the application and working medium.
Diamond Grinding Plates: Consist of a plate body embedded or welded with diamond segments. Driven by the high-speed rotation of the machine, they provide precise and efficient surface finishing.
Applications: Widely used in jade, crystal, agate, handicrafts, as well as electronics, optoelectronics, glass products, vacuum tubes, crystals, and precision industries. Diamond grinding plates are now exported worldwide, including to the Middle East, Southeast Asia, Europe, Hong Kong, and Taiwan.
Grinding plates cannot be used alone and must be paired with grinding or polishing liquids. These liquids serve two main functions:
Cooling: Lowering the working temperature of the grinding process.
Lubrication: Reducing friction and preventing surface damage.
Types of grinding liquids:
Water-based: The simplest form can even be soap water, which is inexpensive but lacks rust resistance, making it unsuitable for metals.
Oil-based: Made by blending organic solvents at specific ratios. While more expensive, they offer superior performance.
By mechanism, grinding liquids can be divided into:
Mechanical action liquids – Contain abrasives such as diamond or boron carbide dispersed in a liquid medium. These are mainly used for coarse grinding, but they may leave scratches that require subsequent fine polishing.
Chemical mechanical action liquids (CMP) – Combine ultra-fine abrasives with chemical agents, achieving high-quality polishing through both mechanical abrasion and chemical corrosion. CMP slurries are widely used in precision industries where a flawless finish is required.
Polishing cloths are essential for improving polishing efficiency and protecting both the polishing plate and medium.
They have a limited lifespan and different specifications may require specific temperature conditions.
Polishing cloth wheels are common consumables for the final finishing step, often referred to as mirror finishing.
The purpose is to remove scratches introduced during grinding and produce a bright, smooth surface.
Self-adhesive – With adhesive backing for easy replacement.
Non-adhesive – Fixed with a pressure ring.
Magnetic backing – With a metal base for magnetic attachment, simplifying installation and removal.
The proper use of grinding plates, grinding liquids, and polishing cloths is crucial not only for achieving high-quality surface finishing but also for extending the service life of polishing machines.
With the right combination of processes and consumables, flat polishing machines can efficiently meet diverse customer requirements—from basic grinding to high-precision mirror polishing.
