About Boring Cutter Processing Skills

The precision of boring processing is very high. The dimensional accuracy of fine boring can reach IT8~IT7, and the aperture can be controlled within 0.01mm accuracy. If it is a fine boring, the processing accuracy can reach TT7-IT6, and the surface quality is good. For general boring, the surface roughness Ra value is 1.6~0.8μm. Let's take a look at how boring should be processed.

Boring steps and precautions

Boring tool installation

It is very important to install the working part of the boring tool, especially for the work adjustment using the eccentric principle. After installing the boring tool, you must pay attention to observe the upper plane of the main blade of the boring tool. Is it on the same horizontal plane with the feed direction of the boring head? Installing on the same horizontal plane can ensure that several chip cutting edges are at normal processing cutting angles.

Boring tool trial boring

The boring tool is adjusted to reserve 0.3~0.5mm margin according to the process manufacturing requirements. The rough boring margin for expansion boring and matching boring is adjusted to ≤0.5mm according to the initial hole margin. It must be ensured that the subsequent fine boring processing margin is met.

After the boring tool is installed and borrowed, a trial boring is required to verify whether the boring tool debugging meets the rough boring requirements.

Boring requirements

*Before boring, carefully check whether the positioning reference of the tooling and workpiece and each positioning element are stable and reliable.

*Use a caliper to detect the diameter of the initial hole to be processed? Calculate how much reserved processing margin is there now?

*Before boring, check whether the equipment (spindle) repeat positioning accuracy and dynamic balance accuracy meet the process manufacturing requirements.

*During the horizontal boring trial boring process, the dynamic runout value of the boring bar gravity overhang must be checked, and the cutting parameters must be reasonably corrected to reduce the impact of centrifugal shear vibration during processing.

*According to the steps of rough boring, semi-finishing boring and finishing boring, the layer boring allowance is reasonably distributed. The rough boring allowance is about 0.5mm; the semi-finishing boring and finishing boring allowances are about 0.15mm, so as to avoid the semi-finishing boring due to excessive allowance, which will affect the adjustment accuracy of the finishing boring allowance.

*For difficult-to-process materials and high-precision boring holes (tolerance ≤ 0.02mm), fine boring processing steps can be added, and the boring allowance is not less than 0.05mm to avoid elastic tool letting on the processing surface.

During the boring tool alignment process, it is necessary to avoid the boring tool working part (blade and tool holder) from impacting the tool block, damaging the blade and the tool holder guide groove, causing the boring tool adjustment value to change and affecting the aperture machining accuracy.

*During the boring process, pay attention to maintaining sufficient cooling and increase the lubrication effect of the processing part to reduce the cutting force.

Strictly remove chips in each processing step to prevent chips from participating in secondary cutting and affecting the aperture machining accuracy and surface quality.

During the boring process, check the wear degree of the tool (blade) at any time and replace it in time to ensure the quality of the hole diameter processing; it is strictly forbidden to replace the blade during the fine boring step to prevent errors; after each step of processing, the process quality control requirements must be strictly implemented, the actual processing hole diameter must be carefully checked and records must be kept to facilitate analysis, adjustment and improvement of the boring process.