What Is The Accuracy of Screw in Different Production Processes？

The precision of lead screw rod is significantly affected by the production process, and there are great differences in precision grade, surface roughness and applicable scenarios among different processing methods. The following are the main production processes and their corresponding precision characteristics:

1. Roll screw

1.1 Process characteristics

Through cold forming of rolling die, high efficiency and low cost, suitable for mass production.

1.2 Accuracy grade

ISO standard: usually IT7~IT9 (low accuracy).

Surface roughness: Ra 1.6~3.2 μm.

1.3 Merits and faults

Advantages: high production efficiency, high material utilization rate, good fatigue resistance.

Disadvantages: poor precision and surface quality, unable to customize non-standard guide.

2. Grind the screw rod

2.1 Process characteristics

The thread is ground point by point through precision grinding machine, which has high accuracy but high cost.

2.2 Accuracy grade

ISO standard: up to IT3~IT5 (high precision).

Lead error: ±0.005~0.01 mm/300 mm.

Surface roughness: Ra 0.4~0.8 μm.

2.3 Merits and faults

Advantages: excellent precision and surface quality, long life.

Disadvantages: long processing cycle, the cost is 3~5 times that of rolled screw.

3. Turning the screw rod

3.1 Process characteristics

Through lathe cutting and forming, it is flexible and suitable for small batch customization.

3.2 Accuracy grade

ISO standard: usually IT5~IT7 (medium accuracy).

Guide error: ±0.02~0.05 mm/300 mm.

Surface roughness: Ra 0.8~1.6 μm.

3.3 Merits and faults

Advantages: flexibility, can be processed large diameter or special materials.

Disadvantages: low efficiency, not as consistent as grinding screw.

4. Cyclone milling screw

4.1 Process characteristics

High speed cutting with cyclone milling cutter is used, and the efficiency is between turning and grinding.

4.2 Accuracy grade

ISO standard: up to IT5~IT6 class.

Guide error: ±0.01~0.03 mm/300 mm.

Surface roughness: Ra 0.8~1.6 μm.

4.3 Merits and faults

Advantages: high efficiency, precision close to grinding.

Disadvantages: large equipment investment, sensitive to tool wear.

5. Precision comparison summary

The actual accuracy of screw rod in different production processes is also affected by material, heat treatment, support mode and other factors.

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