● Improve background

Φ110 hollow silencer spiral tube, produced with conventional national standard formula, impact performance does not meet the requirements of national standard, need to use special formula, formula cost than conventional national standard formula increased by about 244 yuan / ton (about 3.6% higher), and one more formula in the kneading stage is prone to channeling caused unnecessary losses.

Test data of Φ110 hollow silenced spiral pipe (conventional drainage formula)

Test data of Φ110 hollow silenced spiral pipe (special formula)

● Improvement measures

Cause analysis:

1. The size of the inner wall is too thin to absorb enough impact energy

2. The over-dense hole makes the whole pipe have stress concentration phenomenon

3. The lattice rib size is too thin and cannot effectively absorb impact energy

Improvement measures:

1. Adjust the size of the inner and outer walls, the upper limit of the inner wall size and the lower limit of the outer wall;

2. Reduce the number of mold holes, eliminate or reduce stress concentration;

3. Increase the thickness of the ribs, from 1.0 to 1.6-1.8, improve the strength and absorb impact energy.

● Improve the process

1

32 wells → 24 wells (using conventional drainage formula)

32-well test data

24-well test data

conclusion

The 24-hole impact has been improved, but it has not been completely solved, indicating that the above improvement measures can improve the impact performance of the product.

2

24 wells → 16 wells (using conventional drainage formula)

24-well test data

16-well test data

conclusion

Although the wall thickness size of the impact test is qualified, due to the small number of holes, the outer wall shrinks seriously, and an appropriate increase on the basis of 16 holes should solve this problem.

3

16 wells → 20 wells (using conventional drainage formula)

16-well test data

20-well test data

conclusion

The 20-hole Φ110 hollow silenced spiral pipe mold has fully met the requirements of the national standard using conventional drainage formula, and the production is stable, the qualification rate is greatly improved, and there is basically no waste in the case of no abnormal materials. This improvement plan was successful, and the solution entered large-scale production.

After several months of mass production, the performance indicators of the product fully meet the requirements of the national standard, and the production assessment indicators exceed expectations, and this scheme achieves the expected effect.

● Improve the effect

Improvement effect:

-Conventional drainage formula can be used, which saves material costs by 244 yuan/ton (down by about 3.6%) compared with special formulas, and saves about 122,000 yuan/year based on annual sales volume of 500 tons;

-Eliminate quality risks, the performance indicators of the product fully meet the requirements of the national standard, and the production assessment indicators exceed expectations

Continuous Improvement:

Subsequent specifications of hollow silent spiral pipe molds have also been comprehensively modified according to this improvement measure.