Do you know about boring?

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Definition of Boring
Boring: It is a cutting process in which a layer of metal is cut off the machining surface of a workpiece through the relative motion between the boring cutter on the equipment and the workpiece, resulting in a certain machining accuracy and surface roughness of the machining surface

Difference: Compared with other hole processing techniques, boring holes are not limited by tool size; And the boring hole has strong error correction ability, which can correct the error of the original coarse hole axis through multiple tool passes, and can maintain high positional accuracy between the boring hole and the positioning reference

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Types of boring cutters
Type 1
Blade classification: single edge boring cutter/double edge boring cutter/multi edge boring cutter
Processing classification: Through hole boring cutter/Blind hole boring cutter/Step hole boring cutter/Section boring cutter
Structural classification: integral/assembled/modular
Type 2
Single blade boring cutter: integral boring cutter/welding boring cutter/clamp boring cutter/indexable boring cutter
Double edged boring cutter: fixed double-edged boring cutter/floating double-edged boring cutter

Expand the boring cutter Module boring cutter Slotting boring cutter
❹ Ladder boring cutter ❺ Single edge boring cutter ❻ Integral boring cutter
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Application of Boring
When encountering problems, we can first consider these aspects

Rough boring application
1. Blind hole processing

Ensuring correct chip removal is crucial when machining blind holes
The correct cutting parameters are a necessary condition for obtaining the appropriate chip shape
Ensure/check that the chips are not obstructing or wearing the blades
The coolant pressure and cutting fluid flow should be sufficient to discharge the chips
Vertical machine tools have higher requirements for effective chip removal than horizontal machine tools

2.断续切削

When performing intermittent cutting (such as cross holes), high requirements are placed on the cutting conditions of the blade
Choose materials with higher toughness
Under stable working conditions, in order to improve processing safety, choose sturdy square negative front corner basic shape blades
If there are multiple interruptions, reduce the cutting parameters

3.夹砂铸铁

Sand inclusion in castings can increase blade wear.
Choose materials with higher toughness
Reduce cutting parameters
In order to improve processing safety and minimize wear, choose sturdy square negative rake basic shape blades
PS: Sand inclusion refers to the presence of sand inclusions on the casting

4.气烧孔

The local area of the gas burning hole may harden, which will increase the wear of the blade
Choose materials with higher toughness
Reduce cutting parameters
In order to improve processing safety and minimize wear, choose sturdy square negative rake basic shape blades
Precision boring application

1. Cutting force
The impact of cutting force on the product
When the tool is in the cutting state, the tangential and radial components of the cutting force will attempt to cause the tool to deviate from the workpiece. The tangential component will attempt to force the tool downwards and away from the centerline. In this way, the tool clearance angle will decrease
Any radial deformation means a decrease in cutting depth and chip thickness, leading to a tendency towards vibration

2. Balance force
The influence of balance force on machining
The imbalance caused by asymmetric tools or large strokes creates a force acting on the boring tool.
In most applications, the forces generated by imbalance can be negligible compared to cutting forces.
At high speeds, imbalance may cause vibration and affect the machining quality of holes
Note: The following is a summary of on-site processing images for everyone to learn from
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Boring Case
4.1 Blade wear

In boring machining, continuous cutting of the tool can lead to wear and damage, reducing the dimensional accuracy of hole machining and increasing the surface roughness value; At the same time, there are abnormalities in the calibration of the fine-tuning feed unit, resulting in adjustment errors that cause deviations in the machining aperture and even lead to product quality accidents
4.2 Surface quality

Boring fish scale or thread like grooves on the processed surface is a common surface quality phenomenon
Left image: Mainly due to the mismatch between the feed and drilling speed during boring
Right image: Mainly caused by rigid vibration and tool wear during boring machining
Q: How to use spindle positioning during boring tool machining?
A: ① The method of using a dial gauge measuring device to find the correct position requires first using a dial gauge centering device or positioning spindle to determine the coordinates of the reference hole on the workpiece, and then based on the coordinates of the reference hole, determine the coordinate position of the spindle. Its characteristics are high accuracy and convenient operation.
② The characteristic of using inspection rods for alignment and positioning is low accuracy and time-consuming. But this positioning method can directly find the coordinate position between the boring machine spindle and the starting hole.
③ The characteristic of using the interface of holes to align and locate is that it can be used for boring machining of separated box hole systems. The disadvantage is that the assistance time is longer.
④ The characteristic of using a template to find and locate is that the template structure is simple and does not require complex adjustments. But the template is prone to deformation, and when the workpiece needs to process several different hole systems on different surfaces, several templates are needed, resulting in lower alignment and positioning accuracy.