What Is a Broaching? Cutting Process
Knowledge

What Is a Broaching? Cutting Process

The so-called broach refers to the order of size, the rough cutter, and the fine cutter. Most of the cutters are installed on the broaching machine, which is a broach.
Published: Jun 17, 2022
What Is a Broaching? Cutting Process

What Is a Broach?

The broach is a high-productivity, high-precision multi-tooth tool. It can broach various shapes of inner surfaces (such as round holes, polygonal holes, various spline holes, etc.) and outer surfaces (such as grooves at the root of gas turbine blades, external gears, and connecting rods semi-circular holes, and stop planes, etc.). The broach that broaches the inner surface is the inner broach, and the broach that broaches the outer surface is the broach. Most of the broaching knives acting on the broach are pulling force, those under tension are called broaches, and those under pressure are called push knives. Considering the stability of compression, the length of the push knife is short.

There are many forms of movement of the broach during work, some for linear motion, some for circular motion, some for-broach motion, some for-workpiece motion, and some for both at the same time. In most cases, when the broach is working, the workpiece is fixed, and the broach makes a linear cutting motion. The feed movement of the broach is usually accomplished by increasing the size of the tool tooth by tooth. On a general broach, the difference in the height or radius of the adjacent two front and rear teeth is the tooth lift, which can be interpreted as the cutting thickness. The tooth lift of the broach is small, generally only a few percent of mm.

A broach is a special tool, which is more economical to use in mass and mass production. However, if the shape and size of the machined surface have been standardized, the broach can be serialized, organized by the tool factory, and produced in batches. In small batch production, good economic effects can be obtained. Broaching tools for broaching standard round and splined holes are standardized.

What is Broaching?

Broaching is a fast and precise process. Broaching can be used to make round holes, splines, keyways, six-bolt slots, square holes, hexagonal holes, special-shaped holes, spiral internal teeth, etc., which can quickly and precisely cut complex shapes can be customized according to different processing requirements.

Cutting with a broach as a tool. When the broach moves in a straight line relative to the workpiece, the machining allowance of the workpiece is sequentially cut off by the teeth on the broach with increasing sizes. Usually, it can be formed in one working stroke, which is a high-efficiency finishing method. However, due to the complex structure of the broach, the high manufacturing cost, and the certain specialty, broaching is used for mass production. According to different machined surface features, broaching is divided into internal broaching and external broaching.

  • Internal broaching: It is used to process through holes and holes in holes of various cross-sectional shapes, such as round holes, square holes, polygon holes, spline holes, keyway holes, internal gears, etc. Before broaching, there must be a machined hole through which the broach can be inserted. The hole diameter of broaching ranges from 8 to 125 mm, and the hole depth does not exceed 5 times the hole diameter. Under special circumstances, the aperture range can be as small as 3 mm, as large as 400 mm, and the hole depth can be up to 10 meters.
  • External broaching: It is used to process non-closed surfaces, such as planes, forming surfaces, grooves, tongue grooves, blade tenons, external gears, etc. It is especially suitable for processing relatively large planes and composite surfaces in mass production, such as Cylinder blocks, bearing seats and connecting rods of automobiles and tractors, etc. The dimensional accuracy of the broaching profile can reach IT8-5, the surface roughness is Ra2.5-0.04 microns, and the broaching gear precision can reach grades 6-8.

The cutting speed of the broach is generally low, and the commonly used 0.017 ~ 0.13m/s cutting thickness is thin, so the smoothness of the broaching surface is high, the tooth wear is slow, durability and machining accuracy Very high, when machining holes, it can reach 1T7 ~ 9 grades. If there is a squeeze ring at the back of the broach, it can reach 1T6 level. The productivity of the broach is high because the number of working teeth of the broach is large, the cutting edge of each tooth is long, and it can rough and finish at the same time in one working stroke.

Broaching generally uses cutting fluids with better lubricating properties, such as cutting oils and extreme pressure emulsions. In high-speed broaching, the cutting temperature is high, and chemical cutting fluids and emulsions with good cooling properties are often used. If the internal cooling broach is used to inject the cutting fluid into each chip groove of the broach at high pressure, it will have a good effect on improving the surface quality, reducing the tool wear, and improving the production efficiency.

Processing Categories of Broaching:

When broaching, the order and method of removing the machining allowance from the workpiece include forming, gradual, round cutting, and comprehensive round cutting.

  1. Into a form, the machining accuracy is high, the surface roughness is small, but the efficiency is low; the length of the broach is long, and it is used for machining small and medium-sized round holes and forming surfaces with high precision requirements.
  2. The progressive type is suitable for rough broaching of complex machined surfaces, such as square holes, polygon holes, spline holes, etc. The broach used in this method is easier to manufacture, but the quality of the machined surface is poor.
  3. The wheel cutting type has high cutting efficiency and can reduce the length of the broach, but the quality of the machined surface is poor.
  4. Comprehensive wheel cutting method is used for rough broaching by wheel cutting method and fine broaching by forming method. It has the advantages of both and is widely used in round hole broaching.

What Types of Broaching Machines are There?

  • Vertical external broaching machine: The workpiece is fixed on the worktable, and the vertically arranged main slide with the broach broaches the workpiece from top to bottom, with a small footprint.
  • Side broaching machine: Horizontal layout, the broach is fixed on the side-standing slide, and the transmission device drives the workpiece to be pulled down, which is convenient for chip removal. It is suitable for broaching the outer surface of large planes and large allowance, such as the large plane and impeller plate tongue and groove, etc.
  • Continuous broaching machine: Horizontal layout is mostly used, which is divided into workpiece fixing and broaching fixing. The former uses a chain to drive a group of broaches for continuous broaching, which is suitable for large workpieces; the latter uses a chain to drive multiple accompanying fixtures with workpieces to continuously broach through the broaches, which is suitable for small and medium-sized workpieces. A vertical broaching machine can be divided into pull-up types and pull-down types according to the direction of the tool feed. In addition, there are gear broaching machines, internal thread broaching machines, automatic broaching machines, CNC broaching machines, and multi-tool multi-station broaching machines.

What are the Advantages of Broaching?

  • Short processing time and high efficiency:
    Depending on the shape of the workpiece and the amount of cutting, a small workpiece can be completed in about 6 to 30 seconds, and a medium and large workpiece can be completed in about 30 to 90 seconds. The cutting speed is much faster, which is especially suitable for mass production.
  • The high machining precision and small deviation:
    The finished product is dimensionally stable, and the machines and tools used in broaching are designed for mass production. No matter how complex the shape is, the quality data obtained under mass processing is quite stable, and the technical requirements for operators are not high, which can further reduce the quality fluctuation caused by human factors.
  • The machined surface has good surface roughness:
    The machining accuracy is high and the surface roughness is small. Generally, the precision of broaching is ITS-IT7, and the surface roughness R-value is 0.8-0.4um. Due to the low broaching speed and the small thickness of each cutting tooth, the cutting process is smoother and the adverse effects of a built-up edge can be avoided. At the same time, the broach is used for cutting, trimming, and aligning sections. The processing method is economical, and the processing personnel does not need to be skilled to process.
  • It can be processed in different lines and in the same direction:
    It can overcome the shapes that are difficult to machine, and the long hole keyways, splines, and bolt grooves that are difficult to machine by lathes are the advantages of the internal gear broaching machine. The row of teeth that the milling machine takes time to process can be completed in seconds on the external tooth broaching machine. When you encounter shape or output constraints, try the broaching process. Irregular and complex processing surfaces can be in the same direction as the axis, which is easy to process.
  • No need to write a program:
    When replacing different workpieces, if the size is similar, the tool can be replaced. If the size difference is large, the replacement of the jig, broach, and broach head is simple. In the hydraulic broaching machine, the broaching stroke is controlled by the position of the sensor, and the functions used are quite simple. In the servo broaching machine, whether it is collecting processing information or setting the stroke, it can be visualized and operated directly in the man-machine interface, and no programming is required at all.
  • It can be matched with automation:
    By matching with the automatic loading and unloading mechanism, it can achieve all-weather operation, and I/O can be reserved to connect with other equipment and robots in the customer's factory, which greatly reduces labor costs, minimizes unstable factors, and continues to optimize production level.
Published by Jun 17, 2022 Source :tsangsheng

Further reading

You might also be interested in ...

Headline
Knowledge
What is Hardware? Classification of Hardware Accessories
Hardware can be seen everywhere and used everywhere in our lives, especially on some large and small machines, many parts of which are made of hardware. It can be used separately or as an auxiliary, such as hardware tools, hardware parts, daily hardware, construction hardware and security supplies, etc. Let's learn what hardware includes and the classification of hardware accessories.
Headline
Knowledge
What is An Injection Molding Machine? What are The Types?
Injection molding machine, also known as injection machine, is a special machine for manufacturing plastic products. There are many types of injection molding machines, which can usually be distinguished by the following methods: driving mode, mold opening and closing direction, applicable raw materials, mold clamping structure, and injection structure.
Headline
Knowledge
Charging Principle, Method and Introduction of Charging Station for Electric Vehicles
A charging station is a device that supplies electric energy for electric vehicles (including pure electric vehicles and plug-in hybrid electric vehicles), similar to the gas station used in fuel vehicles. How does it work and in what scenarios? Let’s find out.
Headline
Knowledge
What is Quick Die Change System (SMED)?
Quick Die Change (SMED), or 10-minute die change, is a set of useful techniques for dealing with multiple batches of small quantities and improving the rapid response capability of the production system and is a type of lean production method. The point is to convert internal jobs to external job conversions as much as possible.
Headline
Knowledge
Methods and Practical Application Scenarios of Industrial Calibration
Calibration is a quantitative comparison. Check the reading of the instrument, it is achieved by measuring the actual standard part, and the deviation between the measured value and the actual value is corrected.
Headline
Knowledge
What is the Grinding Process and Grinding Wheel?
A grinding wheel is a tool for grinding. It is composed of coarse-grained abrasive compounds bonded together. After forming a solid round object, grinding and abrasive processing can be performed on a grinding machine. Grinding is a commonly used processing method, which can obtain higher workpiece density and surface quality. Different grinding methods will produce different grinding defects. The most influential factor is the grinding wheel.
Headline
Knowledge
What is Knurling?
Knurling is a mechanical process of rolling patterns on the knobs of metal products or other working surfaces, mainly for anti-skid purposes. And used in many hardware, mold, and mechanical components.
Headline
Knowledge
Knowledge of Gear and Gear Transmission in A Mechanical Design!
Gears are mechanical parts with teeth that can mesh with each other to transmit motion and power in mechanical transmission. Gear transmissions stand out due to the accuracy of their gear ratio, which makes them perfect for precision machinery.
Headline
Knowledge
What is the Waste Plastic Granulation Process?
The waste plastic granulation process is the process of metering, bonding, plasticizing and granulating polymer resin and various waste plastics and additives into granular plastics, which are semi-finished products in the plastic molding processing industry.
Headline
Knowledge
Analysis of the Advantages and Disadvantages of Electric Tools and Pneumatic Tools!
When it comes to maintenance tools, many people strongly recommend electric tools, which have many varieties, easy to use, and low prices, especially suitable for home use. But you know what? There is also a powerful and efficient tool in the tool industry, that is, pneumatic tools. So, what is the difference between the two, and how should one choose? Let this article tell you now.
Headline
Knowledge
What is the Granulation Process and its Function?
With the wide application of plastic products, the disposal of waste plastics has become a difficult problem and an urgent issue that needs to be solved in global environmental pollution. Therefore, it can be partially reused through the plastic granulation process.
Headline
Knowledge
Understand Passive Components in Minutes
Any electronic product must use two components, so-called "active components" and "passive components". "Active components", as the name suggests, are components that can actively perform operations independently, while "passive components" play a passive protective role. When an electronic product changes current or voltage, the role of "passive components" is to protect "active components" by means of low voltage, filtering noise, etc. To put it simply, "passive components" with low unit prices are always ready to protect the safety of "active components" with high unit prices.
Agree