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how to choose milling method

May. 30, 2022

Milling is a common type of CNC machining and many kinds of parts choose this method for the production, here we give a simple introduction to it.

1. Face milling

Whenever possible, milling of planes with the intersection of grooves and holes should be avoided, since this will cause the cutting edges to work in unsatisfactory interrupted cutting conditions. A hole-making operation should be carried out after milling. If this option is not possible, then when the cutter crosses the hole, you need to reduce the feed rate by 50% of the recommended. When machining large planes, you should try not to interrupt the contact of the cutter with the workpiece, bypassing the surface around the perimeter, and not in several parallel passes. Corner processing must be carried out along a radius exceeding the cutter radius to exclude the possibility of vibrations associated with a sharp increase in the cutter wrap angle.

2. Milling narrow grooves

A long and narrow groove cannot be machined using circular interpolation but must be done in a single pass over the full groove width. If the power of the equipment allows, it is advisable to choose the cutter diameter as close as possible to the final size of the groove. After such processing, there will be a minimum finishing allowance. For pre-drilling the groove, it is recommended to choose a drill with a diameter of 5 … 10 mm larger than the cutter diameter. The maximum drilling depth should be no more than the cutter diameter. It is necessary to reduce the feed at the start of cutting to ensure reliable chip evacuation.

3. Drilling and plunge milling

It is necessary to choose a drill with a diameter Dc 1 mm larger than the cutter diameter. Maximum radial cutting depth 12 mm (at Dc = 50 mm). The number of teeth simultaneously participating in cutting must be equal to two.

4. Plunging in two axes

The maximum infeed angle depends on the cutter diameter (for a Dc = 50 mm cutter, the infeed angle is 5). For maximum machining performance, select 12mm or 16mm inserts and a small pitch cutter.

Milling technology for parts with conjugate planes and polyhedrons. Mating surfaces of one part, that is, surfaces located in different planes, can be parallel, perpendicular, or located at any angle. Such planes include adjacent faces of a rectangular and square prism, cube, hexagon, pyramid, etc.

Processing of workpieces with conjugate planes is carried out on vertical and horizontal milling machines with end, end, and cylindrical mills, as well as sets of milling cutters. On the machine table, workpieces are fixed in universal or special devices.

5. Processing of polyhedra

When milling a square from a bar, the workpiece, depending on its length, can be fixed in one of the following ways:

* in a three-jaw chuck;

* in the three-jaw chuck and the centre of the tailstock;

* in the centres of the universal dividing head and tailstock. Milling the edges of the squares is done with end, end, and disc cutters.

When machining hexagons, high productivity can be achieved using a set of disc cutters. Machining of planes conjugated at acute and obtuse angles is carried out in the same way as for inclined planes. The relative position of the conjugate planes (parallel and perpendicular), machined with the resetting of the workpieces in the vice of a universal horizontal milling machine, is controlled by vernier callipers, and squares, curved rulers, and planers.

The planes located at obtuse and acute angles are controlled by templates and planers, regardless of which cutters are used for this processing: cylindrical or end cutters.

Considering the Materials for CNC Milling

All programmable milling machines are equipped with the ability to adjust the power, the feed rate of the warp, and the choice of cutting mode. A wide range of settings allows you to use a wide variety of materials for cutting:

* wood, plywood, chipboard, fiberboard, MDF;

* PVC plastic;

* composite;

* polystyrene, PET;

* acrylic and organic glass;

* metal

Aluminium milling

Aluminium is in great demand in almost all areas of industry and high technology. Parts made of this metal are lightweight, resistant to corrosion and aggressive chemical compounds, and have a low melting point.

CNC devices have changed the look of the production hall. They control turning, drilling, milling, and grinding machines, greatly speeding up and simplifying human work. Almost every enterprise that deals with the mechanical processing of parts have a computerized system. CNC milling provides manufacturing facilities with new opportunities to improve product quality and increase profitability.

Xu Feng focused on CNC milling for over 15 years, we have rich experience in different structure and material milling, if you have any questions about it, feel free to contact us for the details.