Milling machine processing right angle grooves

Milling right angle grooves with milling machine generally has three kinds, namely slot, half-slot and closed groove. The right angle groove is mainly milled with a three-edge milling cutter and can be milled with an end mill and a keyway cutter. Half pass and closed grooves are milled with end mills or keyway milling cutters.

1. Use a three-edged cutter to cut the right angle groove

(1) Milling cutter selection

The width of the milling cutter L≦B; the diameter of the milling cutter D>d+2H. Where B is the groove width to be machined; d is the diameter of the cutter bar gasket; H is the groove depth, D, L is the cutter diameter and width.

(2) Workpiece clamping and correction

Under normal circumstances the use of flat clamp clamp workpiece. When the slot is slotted, the fixed jaws of the flat clamp should be perpendicular to the axis of the milling machine spindle.

(3) Commonly used tool setting method

1) Marking method. Draw the dimension line and position line of the right angle groove in the machining part of the workpiece.

2) Sticker method is shown in figure.

In actual production, two methods are used in coordination.

2. End milling cutter milling half-pass and closed groove

When using an end milling cutter to mill half a slot on a milling machine, select the end milling cutter diameter to be equal to or less than the width of the groove. Due to the poor rigidity of the end mill, milling is easy to produce "partial" phenomenon, the depth of the deep groove, the number of points should be milling to the required depth. Milling to the depth, then the two sides of the slot to the size of the milling. Expansion milling should avoid smooth milling, to prevent damage to the cutter and bite the workpiece.

When the milling cutter is closed with an end mill, it should be pre-drilled at one end of the groove before milling.

3. Use a keyway cutter to mill half-pass and closed groove

High precision, shallow depth of the half-pass and closed groove, can be used key milling cutter milling. The end face cutting edge of the keyway cutter can cut the workpiece when the milling machine is vertically fed. Therefore, it is not necessary to drill down the hole with the keyway cutter to cut through the closed groove.

4. Measurement of right angle grooves

The measurement of the length, width and depth of the right-angled groove generally uses the vernier caliper and the depth vernier caliper. Slot width limit gauge (key groove plug) check. The symmetry of the groove is tested with a vernier caliper or dial indicator.

Milling machine processing steps

The technical requirements of milling machine processing steps and right angle grooves are dimensional accuracy, parallelism, perpendicularity, symmetry and inclination.

1. Steps milling method

The steps are usually machined on a horizontal milling machine with a three-edge cutter or a face milling cutter or an end mill on a vertical milling machine.

(1) With three blade cutter milling steps

Three-edge milling cutter with straight and wrong teeth two. Large diameter teeth of the three teeth cutter, mostly for the tooth-type structure, when a knife after the damage, the replacement of a knife can be. Three sides of the cutter diameter and knife size are relatively large, the strength of the teeth on the large, chip removal, cooling better, higher production efficiency. Therefore, the general use of three-edge milling cutter milling steps. When milling, the three-edge milling cutter cylindrical cutting edge mainly from the cutting effect, the two side cutting edge from the role of light.

1) With a three-sided milling cutter milling steps

①Milling cutter selection. The width should be greater than the step width, that is, L> B, diameter should be calculated according to D> d +2t. Where D is the diameter of the three-edge cutter; d is the outer diameter of the milling rod washer; t is the step depth. In order to meet the requirements of the use of the premise should be used in smaller diameter three blade cutter.

②Workpiece clamping and correction. General workpiece can be used flat clamp clamp, larger size of the workpiece can be used pressure plate clamping, complex shape of the workpiece or mass production can be used special fixture clamping.

③Milling method. After the workpiece is clamped, cut the paper. When the step depth is deep, multiple milling is used. The last time the feed, the bottom of the steps and the side of the same time fine grinding to the technical requirements.

④With a three-blade cutter milling double-sided stage. as the picture shows. The first step, the milling side of the steps to the size requirements, and then exit the workpiece, the milling machine table horizontal feed a distance A, tighten the horizontal feed mechanism after the rough, fine milling the other side; or side of the rough. After milling, loosen the flattened pliers, turn the workpiece 180°and then re-clamp, fine milling the other side of the steps, and then turn 180°fine milling the other side of the steps. This method of milling can achieve a higher degree of symmetry.

2) Combination of three blade milling cutter milling steps for mass production. This method not only can improve the production efficiency, but also simple operation, and can guarantee the quality of the workpiece. But the diameter of the two three-edge cutter should be the same, with a cutter rod washer to adjust the two cutting edge of the cutter blade between the cutting edge of the distance between the two milling cutter should be staggered half a tooth to reduce the milling vibration.

(2) Face milling cutter milling steps

Wide width and shallow depth of the steps, often use the face milling cutter in the vertical milling machine processing. Face milling cutter knife strength, milling, chip thickness changes in small, smooth cutting, processing surface quality, high productivity. Face cutter diameter generally take (1.4 ~ 1.6) B.

(3) With an end mill milling steps

Deep step or multi-step steps can be machined with an end mill on a vertical milling machine.

2. Step measurement

Generally measured with a vernier caliper, depth vernier caliper. When the dimensional accuracy is high, it is measured with an outer diameter micrometer or a depth micrometer. Large volume can be used when the limit gauge detection.

Milling machine processing slope

There are many ways of milling slope on milling machine, including workpiece tilting method, milling cutter tilting method, angle milling cutter milling slope and so on.

(1) workpiece tilt method

In the use of horizontal milling machine or vertical milling head milling slope, the workpiece can be tilted after the required angle of clamping, milling. Commonly used methods are the following.

1) According to the scribing of the workpiece milling slope. When the production of a single piece, first draw the slope of the processing line, and then use the flat clamp clamp, and then use the scribe line to find the horizontal position of the processing line, with a cylindrical milling cutter or face milling cutter out of the slope.

2) pull the flat mouth clamp clamp workpiece milling slope. Install the flattened pliers, the first fixed jaws and the milling machine spindle axis perpendicular or parallel, and pull the clamp to the desired angle, and then clamp the workpiece and milling.

3) Tilt the workpiece with an inclined horn. Use the tilting horn to tilt the workpiece datum as shown. The inclination of the oblique iron is equal to the inclination of the ramp and the width of the horn should be less than the width of the workpiece.

(2) milling cutter tilting method

Install a end mill or face milling cutter on a vertical milling machine with a rotatable angle at the vertical milling head, clamping the workpiece with a flattened pliers or platen, and milling the ramps. Commonly used methods are the following two.

1) The workpiece base is parallel to the table. With the face milling cutter or the end face of the end mill milling the slope, the vertical milling head should be rotated by the angle α=θ, as shown in the figure; with the end mill cutting edge of the slope, Of the angle α= 90°-θ, as shown.

2) Workpiece reference plane and milling table vertical clamping. When the slope is milled with the circumferential edge of the end mill, the angle of the vertical milling head should be tilted α=θ, as shown in the figure. When milling with an end mill or the end face of the end mill, of the angle α= 90°-θ, as shown.

(3) With the angle milling cutter milling slope

The narrower bevel can be cut with an angle milling cutter. Select the angle of the angle of the milling cutter should be based on the angle of the workpiece slope, the width of the milling should be less than the width of the cutting edge of the cutting edge. Milling the symmetrical double bevel, you should select two diameters and angles the same, the cutting edge of the opposite angle milling cutter at the same time milling, milling cutter should be installed when the two cutter blade staggered to reduce the milling force and vibration, as the picture shows. As the angle cutter cutter blade strength is weak, the teeth are arranged in a more dense, milling more difficult when the chip, so the amount of milling should be about 20% lower than the cylindrical cutter, especially the feed per tooth is more appropriate to reduce. When the milling machine milling carbon steel and other parts, should be sufficient to apply cutting fluid.

Milling machine milling vertical and parallel planes

Milling of vertical and parallel planes with milling machine are often used in actual machining operations. It is necessary to understand and master the practical milling method.

1. Circular milling vertical plane

A vertical plane is a plane that is perpendicular to the reference plane. There are three ways to cut a vertical plane with a circular milling cutter.

(1) Milling is done with a flattened clamp on a horizontal milling machine

Clamp the vertical plane with a flattened clamp to fit the smaller workpiece.The main factors affecting the verticality of the following points: fixed jaw face and the work surface perpendicularity error. The datum does not fit tightly with the fixed jaws. Circular milling cutter has a large degree of cylindrical error. The flatness of the datum plane is large. Clamping force is too large and so on.

(2) In the horizontal milling machine with angle iron clamping for milling

Applicable to the workpiece surface is relatively wide and relatively narrow processing of the workpiece milling.

(3) Milling with an vertical mill cutter on a vertical milling machine

For the base width and long, narrow processing of the workpiece, you can use the end mill on the machine tool processing.

The main factors affecting the vertical degree are: vertical feed, the end of the cylindrical milling die error; horizontal feed, the end of the milling cutter cylindrical error, vertical milling head spindle axis and vertical feed direction of the vertical error Big.

2. Milling the parallel plane with a circular milling cutter

A parallel plane is a plane parallel to the reference plane. Milling the parallel surface with a circular milling cutter, usually in a horizontal milling machine with a flattened clamp clamp for milling. The main factors affecting the parallelism are: the base plane and the flat mouth clamp clamp body surface is not parallel; flat mouth clamp clamp body surface and milling machine table table is not parallel; cylindrical milling cutter cylindrical error and so on.

3. Milling the vertical and parallel planes with a face milling cutter

(1) vertical plane milling

1) with a flat clamp clamp, end milling vertical surface.

2) in the machine table on the table surface clamping, end milling vertical surface, as shown in the figure.

(2) parallel plane milling

1) Milling the parallel plane on the top of the vertical milling machine, as shown in the figure.

2) Milling the parallel plane at the top of the horizontal milling machine, as shown in the figure.

Milling machine plane milling quality analysis

In this article, we will discuss the factors that affect the quality of the milling machine milling plane and the points of attention during the milling process.

1. Factors affecting flatness

①The cylindricity error of circular milling cutter in circular milling; the verticality of spindle axis and feed direction of milling machine in end milling.

②The deformation of the workpiece under the influence of clamping force and milling force; the internal stress of the workpiece causes the deformation of the part after milling; the milling heat causes the thermal deformation of the workpiece.

③Milling machine table feed linearity error; milling machine spindle bearing axial and radial clearance.

④When milling, the width of the circular cutter or face milling cutter diameter is less than the width of the workpiece and then knife, resulting in knife marks.

2. Factors affecting surface roughness

①The milling cutter wears and the tool edge becomes dull.

②Feed rate and cutting thickness are too large.

③Milling cutter geometry parameter is not proper; milling vibration is too large; milling has the phenomenon of knife dragging.

④When milling, the choice of cutting fluid is not good. When milling, there is the accumulation of chips or the phenomenon of chip sticking.

⑤In milling, the feed stop causes the milling cutter to sink and cut out the pit on the machined surface of the workpiece.

3.Matters needing attention

(1)Milling before milling cutter, milling head, workpiece clamping is solid, the installation location is correct.

(2)Before starting to pay attention to whether the cutter head and the workpiece with the workpiece, flat pliers hit.

(3)After the cutter is rotated, check whether the direction of rotation of the cutter is correct.

(4) You should be turned on the knife to adjust the amount of knife; if the handle over the head, to eliminate the screw and nut gap, so as not to milling the wrong size.

(5)Milling is not allowed to touch the workpiece and milling cutter, are not allowed to measure the workpiece, not allowed to change the feed.

(6)Milling is not allowed to stop the cutter rotation and automatic feeding table, so as not to damage the tool, gnawing the workpiece.

(7) After the feeding is completed, the workpiece can not be immediately returned under the rotating cutter. Should first drop the milling machine table, and then exit the workpiece.

(8)Not use the feed mechanism should be tightened, after work and then release.

(9)When use flat mouth clamp clamp workpiece, it should be removed in the flat wrench and then automatically feed the workpiece.

(10)Chip should fly to the side of the milling machine bed, so as not to burn the operator.

(11)Knife test cut, adjust the installation of the cutter head, be careful not to damage the blade edge.

(12)Such as the use of four milling head, the head can be installed into a stepped cutting workpiece.

Milling machine circular milling and end milling(Continued)

The milling machine has two kinds of milling methods, forward milling and reverse milling. When forward milling, the effect of the cutter on the workpiece is the same as the feed direction of the cutter in the feed direction. Reverse milling is the opposite direction.

1. Advantages and disadvantages of circular forward milling

When the forward milling is done, the force on the workpiece is reduced by the force of the workpiece, the milling is smooth, it is suitable for the workpiece which is not easy to be clamped and the slim parts are slim. Cutting edge and the machined surface of the extrusion, friction is small, high quality processing surface. Consume less power. However, when cutting the cutting edge into the workpiece, easy to accelerate the tool wear and damage. Milling force Ff and workpiece feed the same direction, when the table feed screw and nut gap and bearing the axial clearance is large, the milling machine table will produce intermittent movement, resulting in tooth damage, knife The rod is bent and the workpiece and the fixture are displaced. As the picture shows.

2. Advantages and disadvantages of circular reverse milling

In inverse milling, cutting edge along the machined surface of workpiece, surface crust on the cutting edge of small damage. The Ff is opposite to the feeding direction of the workpiece without the movement of the milling machine table. But the Fn is always upwards and requires greater clamping force. The extrusion and friction of the cutting edge and the workpiece surface are serious, which accelerates the cutting edge wear, reduces the life of the milling cutter, and produces a hardened layer on the machined surface of the workpiece, thus reducing the processing quality of the workpiece surface. The power consumed in feed motion is greater.

Reverse milling is generally used when milling a circle on a milling machine. When the screw nut transmission pair, the axial clearance is 0.03~0.05 mm, Ff is less than the friction between the rail milling machine, milling is not easy to thin and slender workpiece, also can choose forward milling.

3. Forward milling and reverse milling in end milling

According to the relative positions between the milling cutter and the workpiece, end milling is divided into two kinds, symmetrical milling and asymmetrical milling. End milling also has forward milling and reverse milling.

(1) Symmetrical milling

In the end milling, the center of the workpiece is in the center of the milling cutter. In symmetrical milling, half is reverse milling, half is forward milling. Symmetrical milling is used when the side knife is close to the cutter diameter.

(2) Asymmetric milling

According to cut into the edge and cut out the side of the amount of knife to eat the ratio is divided into asymmetric forward milling and asymmetric reverse milling. Asymmetric forward milling along the milling part of the proportion of large, end milling generally do not use this method. In the milling machine milling plasticity and toughness is good, hardening of hardening materials, such as stainless steel, heat-resistant alloy steel, etc., the use of the method. The proportion of the counter-milling part of the asymmetric inverse milling is larger and the method is generally used for end milling.

Milling machine circular milling and end milling

Circular milling and end milling are two ways often used in milling machine processing. Here we compare the two characteristics of the two methods and their differences.

1) Milling cutter blade is short, good rigidity, the number of teeth involved in milling more, so the vibration is small, smooth milling, high efficiency.

2) The diameter of the face milling cutter can be made very large, can be a single surface milling without the need to pick up the knife. Circular milling, the width of the workpiece surface by the cylindrical milling cutter width can not be too wide.

3) Milling cutter blade easy to install, good rigidity, suitable for high-speed milling and strong milling. It can improve the milling machine productivity and reduce the surface roughness value.

4) Milling cutters the cutting thickness of each knife is small, so the milling force changes little during end milling.

5) In the milling layer width, depth and the same feed per tooth under the conditions of the surface cutter does not use the repair edge and high-speed milling and other measures, can be milling. But the end milling is greater than the surface roughness produced by the circular milling.

6) Circular milling can cut a large amount of side knife.

The end milling plane has more advantages, and the milling machine with a circular milling cutter is replaced by a face milling cutter plane on many occasions.