High-Precision Grinding Manufacturer: The Differences Between Manual and Machine Flat Grinding

High-precision grinding The manufacturer specifies that manual grinding typically employs a single plate made of high-carbon cast iron, with the plates supplied in sets of three. The flatness tolerance for each plate is also specified.

1. Cast iron grinding disc with built-in abrasive sand

Embedded abrasive (sand) involves first embedding abrasive particles into the surface of the grinding plate. This technique is difficult to master and serves as a critical gateway to ensuring work quality. It can be carried out manually or mechanically, but mechanical methods struggle to guarantee consistent quality; therefore, manual sand‑embedding is the more common approach. Prior to performing the sand‑embedding operation, a “sand‑stripping” step must be completed. Sand‑stripping entails removing worn, no longer effective abrasive material from the grinding plate’s surface, thereby preparing the plate for the next sand‑embedding process.

2. Sand Placement Procedure

Taking W1 corundum abrasive as an example, the procedure for embedding the abrasive in sand is described. First, wipe both grinding plates clean with degreasing cotton. Then apply stearic acid. Place the prepared abrasive mixture—corundum, stearic acid, and aviation gasoline—on the surface of the grinding plate, using approximately 15 to 20 milliliters. Spread it evenly by hand and allow the gasoline to evaporate completely. Next, add 3 to 5 drops of kerosene and distribute it uniformly. Lock one grinding plate onto the other, and have two people press down in a “T” shape, ensuring the upper plate oscillates smoothly and evenly while intermittently rotating through 180 degrees. Repeat this back-and-forth motion several times (5 to 10 cycles). Remove the upper grinding plate, wipe it clean with degreasing cotton, and continue until the plate turns black. Finally, inspect the result using test blocks to evaluate cutting force, scratch density, and uniformity of thickness. Typically, internal‑grit sanding requires 4 to 5 passes.

A high-precision grinding manufacturer discusses machine grinding.

Mechanical lapping involves grinding a workpiece against a rotating abrasive material, typically a circular lapping plate. The abrasive material for mechanical lapping is usually cast iron, with discs made of steel or copper also employed. Felt and silk‑covered plates are frequently used for lapping sealing rings made of cemented carbides, copper alloys, stainless steels, and similar materials. The surface of metal lapping plates must be flat and free of defects, with flatness maintained at 0.05 mm per 1,000 mm or better. The disc’s radius should be designed to exceed twice the diameter of the workpiece being processed. High‑precision lapping manufacturers generally specify diameters ranging from 305 to 1,620 mm (16 to 64 inches), with a thickness approximately one‑tenth to one‑sixth of the diameter. As shown in Figure 9‑32, grooves machined into the disc surface serve to reduce stress‑induced deformation, facilitate heat dissipation, remove spent abrasive particles during lapping, and accommodate debris.

Heavy-duty surface grinder

This is a single-sided grinder, commonly used for the grinding of heavy-duty sealing rings and is one of the most widely employed types of grinders.

The high-precision grinding manufacturer states that the main technical parameters include:

The maximum workpiece diameter is 3360 × 240 mm. The minimum workpiece thickness is 1 mm. Machining accuracy is 0.03 mm, with a surface roughness of Ra 0.05 µm. The grinding machine has a wheel diameter of 650 mm, a speed range of 10–60 r/min with stepless variable speed, and a motor power of 1.5–2.2 kW. The ring diameter X controls the inner ring diameter at 3360 × 280 mm × 240 mm. Overall dimensions (length × width × height) are 900 mm × 1000 mm × 800 mm. Weight: 1200 kg.

Pneumatic grinder

The high-precision grinding manufacturer believes that this grinder has the following features:

The grinding disc rotates at a speed controlled by a variable-speed motor and a reducer, offering a compact footprint, high efficiency, smooth operation, and low noise. With a transmission ratio of 1:20, the grinding disc can reach speeds of up to 150 r/min, as indicated on the dashboard by the motor’s rotational speed.

This machine features adjustable operating time; set the maximum duration to 100 minutes. Once the grinding‑machine timer is configured, it will run continuously until the preset time is reached, at which point the machine automatically shuts off, making the grinding process more convenient.

The abrasive has excellent adjustment capabilities. After loading the prepared abrasive into the storage tank, electromagnetic stirring prevents sedimentation of the abrasive particles. By utilizing pneumatic pressure and a solenoid valve within the tank, the interval for adding abrasive can be adjusted up to 100 minutes, and the duration of each abrasive addition can also be customized. The instrument panel displays the abrasive‑addition interval in minutes per cycle.

Dongguan Fulin Machine Co., Ltd. specializes in wire EDM, high-precision grinding, slow-wire EDM, mechanical parts, multi-axis machining, CNC machining, five-axis machining, precision parts, non-standard parts, and general machining. The company boasts state-of-the-art production equipment and is equipped with advanced inspection instruments, such as coordinate measuring machines, microscopes, projectors, hardness testers, 3D measuring devices, and Swiss height gauges, ensuring the production and processing of high-precision products to meet customer requirements. To date, we have maintained successful long-term collaborations with numerous related enterprises, and our product quality has consistently earned customers’ recognition and praise. Our unwavering commitment is to put people first, excel through quality, foster unity and progress, and pursue continuous innovation—satisfying our customers by delivering superior quality, honoring precise delivery schedules, providing exceptional service, and ensuring customer satisfaction through systematic management.