What are the reasons for poor tooth surface roughness

Writer： admin Time：2024-05-09 14:39:29 Browse：61℃

Due to reasons related to machine tools

The precision of components in the machine tool transmission chain, such as the tool spindle and worktable spindle, has been lost or worn, and the gap between the transmission components has increased, resulting in looseness and impact during cutting;

The contact between the spindle of the workbench and the conical guide surface of the workbench is too hard, causing the workbench to drive heavily, resulting in friction and heat generation during rotation, causing vibration; Or if the contact is too loose, the workbench may shake during operation;

The tool holder body and the two indexing worm gear of the workbench have excessive axial displacement during operation, or the meshing gap between the worm gear and the worm gear is too large, causing jumping during operation;

The cutting mechanism of the machine tool is not working properly, and the machined surface of the workpiece is scratched when the gear cutter returns.

Solution:

Identify parts with lost accuracy for repair, correction, or replacement;

Scrape the surface of the conical guide rail to ensure even contact and no sense of weight within one revolution;

After grinding and adjusting the gasket and replacing the bearing, ensure that its axial displacement is within 0.005 and maintain a reasonable meshing clearance between the worm gear pairs;

Readjust the cutting mechanism, especially when the machining modulus is greater than 4 or smaller, this phenomenon occurs more frequently.

Reasons related to cutting tools

The cutting edge of the gear cutter has been worn dull, causing tearing of the tooth surface of the inserted gear;

During the slotting process, the slotting cutter generates chip deposits that adhere to the cutting edge. However, during the grinding process, the sticking part is not removed, which improves the surface roughness of the cutter teeth;

The front angle of the gear shaping cutter should be adapted to the material of the gear being inserted. For example, when cutting alloy materials after quenching and tempering, if a gear shaping cutter with a front angle of 5 ° is still used, it is easy to produce chip deposits during cutting;

The gear cutter is not tightened properly after installation, resulting in displacement and vibration during cutting.

Solution:

Re sharpen the gear cutter to make the edge sharp, and cool it thoroughly during sharpening to improve the grinding quality of the front blade surface;

Appropriately increase the number of reciprocating strokes of the gear shaping cutter to prevent the formation of chips and nodules;

Appropriately increase the front angle of the gear shaping cutter;

Reinstall and tighten the gear cutter.

Due to reasons related to installation, cooling, workpiece material and machine heat treatment

Improper or dirty cutting fluid selection;

The installation of the gear blank is not firm, causing displacement and vibration during cutting;

The material hardness is too high, causing defects such as tearing and fish scales on the tooth surface.

Solution:

Reasonably choose cutting fluid and replace it in a timely manner if it is too dirty;

Check if the gear blank is tight;

Pre heat treatment of gear blanks