chengcg – Page 16 – CNC Machining & Turning, Milling, Metal parts

CNC machining raw material cutting grade

In the field of mechanical processing industry, the main raw materials are aluminum, copper, POM steel, stainless steel, die steel, Unilever rubber and so on. According to the hardness of materials, reasonable cutting tools and processing technology will be selected. The processing of raw materials for general equipment spare parts is divided into grades. Take a look at the following grades:

General non-ferrous metals: machinability grade (1), machinability of materials. Easy to process, relative machinability K: 8-20, representative materials: aluminum magnesium alloy, 5-5-5 copper lead alloy;
Free cutting steel: machinability grade (2), machinability of material. Free cutting, relative machinability K: 2.5 ~ 3, representative material: automaton steel（ σ b＝400～500MPa);
Free cutting steel: machinability grade (3), machinability of material. Free cutting, relative machinability K: 1.6 ~ 2.5, representative material, 30 steel normalizing（ σ b＝500～580MPa）;
Machinability grade of general carbon steel and cast iron (4), machinability of materials, general relative machinability K: 1.0-1.5, representative materials, 45 steel and gray cast iron;

5, machinability grade (5) of slightly difficult cutting materials, machinability of materials, common relative machinability K: 0.7-0.9, representative materials, 85 rolling, 2Cr13 quenching and tempering（ σ b＝850MPa）

6, machinability grade (6), machinability, relative machinability K: 0.5-0.65, representative material, 65Mn quenching and tempering（ σ B = 950-1000mpa), free cutting stainless steel;

7, machinability grade of hard cutting material (7), machinability of material, relative machinability K: 0.15-0.5, representative material, stainless steel (1Cr18Ni9Ti); 8, it is difficult to cut the material to be machinability grade

(8) The representative materials are heat resistant alloy steel and titanium alloy

The above is the raw material cutting grade sharing, thank you for your attention!

ken. tang@chengcg.com

Introduction of CNC milling cutter

In the process of precision machining, the common milling machine tools are dial indicator, minute bar, center drill, drill and milling cutter, etc. the milling cutter used in precision machining has a variety of commonly used types according to the use classification.

Cylindrical milling cutter: used for machining plane on horizontal milling machine. The cutter teeth are distributed on the circumference of the milling cutter and can be divided into straight teeth and spiral teeth according to the tooth shape. According to the number of teeth, it can be divided into coarse teeth and fine teeth. The helical coarse tooth milling cutter is suitable for rough machining because of its small number of teeth, high tooth strength and large chip space; Fine tooth milling cutter is suitable for finishing after grinding.
Face milling cutter: it is used for vertical milling machine, end milling machine, gantry milling machine and upper machining plane. There are cutter teeth on the end face and circumference, as well as coarse teeth and fine teeth. Its structure has three types: integral type, inlaid type and indexable type.
End milling cutter: it is used for machining groove and step surface. The cutter teeth are on the circumference and end face, and cannot feed along the axial direction when working. When the end milling cutter has an end tooth passing through the center, it can be fed axially (usually the double-edged end milling cutter is also called “keyway milling cutter” which can be fed axially).
Three side milling cutter: it is used to process all kinds of grooves and step surfaces, with cutter teeth on both sides and circumference.
Angle milling cutter: it is used for milling groove with certain angle. There are two kinds of single angle milling cutter and double angle milling cutter. Generally, it processes dovetail groove.
Saw blade milling cutter: it is used for machining deep groove and cutting workpiece, with more cutter teeth on the circumference. In order to reduce the friction during milling, there are 15 ‘- 1 ° The secondary deflection angle of the system. In addition, there are keyway milling cutter, dovetail milling cutter, T-groove milling cutter and various forming milling cutters. According to the different parts processing technology, choose the appropriate milling tool.

There are four kinds of milling cutter structures that are often used.

Integral type: the cutter body and cutter teeth are integrated.
Integral welding tooth type: the cutter teeth are made of cemented carbide or other wear-resistant tool materials and brazed on the cutter body.
Inlaid type: the cutter teeth are fixed on the cutter body by mechanical clamping. The replaceable cutter teeth can be the cutter head of the whole cutter material or the cutter head of the welding cutter material. The milling cutter with the cutter head mounted on the cutter body for grinding is called internal grinding type; If the cutter head is grinded separately on the fixture, it is called external grinding.

4, indexable: this structure has been widely used in face milling cutter, end milling cutter and three face edge milling cutter, etc.

The above is the classification of milling cutters commonly used in precision machining. Thank you for sharing!

ken. tang@chengcg.com

Introduction of CNC parts processing fixture

In the field of machining industry, some complex parts are difficult to process, and auxiliary fixture will be used. There are many kinds of auxiliary fixtures to be contacted. Let’s see what the difference is

First of all, understand the general fixture: General fixture refers to the standardized fixture that can be used to process different workpieces within a certain range. For example, three jaw chuck and four jaw single action chuck on lathe, flat tongs, dividing head and rotary table on milling machine, etc. This kind of fixture is usually produced by professional factories and is often provided to users as machine tool accessories. It is characterized by wide adaptability and low production efficiency. It is mainly suitable for the production and processing of single and small batch parts; Special fixture: special fixture refers to the fixture specially designed for a certain process of a workpiece. It is characterized by compact structure, fast, convenient and labor-saving operation, which can ensure high machining accuracy and production efficiency of parts, but the design and manufacturing cycle is longer and the manufacturing cost is higher. When the product is changed, the fixture will be scrapped because it can no longer be used. It is only suitable for the production and processing with fixed products and large batch; Universal adjustable fixture and group fixture: its feature is that some components of the fixture can be replaced and some devices can be adjusted to adapt to the processing of different parts. The fixture used for group machining of similar parts is called group fixture. Compared with the group fixture, the general adjustable fixture is not very clear about the processing object and has a wider range of application.

There are modular fixture: modular fixture is a fixture assembled by a set of pre manufactured standard components and parts according to the processing requirements of mechanical parts. It is made by professional manufacturers. It is characterized by flexibility, versatility, short manufacturing cycle and repeated use of components. It is especially suitable for trial production of new products and small batch production and processing of single piece. Accompanying fixture: accompanying fixture is a kind of fixture used in automatic line. The fixture not only plays the role of clamping the workpiece, but also integrates with the workpiece to move from one station to the next along the automatic line for different processes.

In the process of machining mechanical parts, according to the classification of machine tools used: due to the different working characteristics and structural forms of all kinds of machine tools, different requirements are put forward for the structure of fixtures. According to the different machine tools used, fixtures can be divided into: lathe fixture, milling fixture, drilling fixture, boring fixture, grinder fixture, gear fixture and other machine fixture. According to the classification of clamping power source: according to the different clamping power source used by the fixture, it can be divided into: manual fixture, pneumatic fixture, hydraulic fixture, gas-liquid fixture, electric fixture, magnetic fixture, vacuum fixture, etc.

The above is the mechanical parts processing auxiliary fixture introduction, thank you for sharing!

ken. tang@chengcg.com

Technical problems of milling machine

In the process of mechanical parts processing, general parts processing technology often contact with the completion of turning and milling machine. And turning and milling machine processing mechanical parts, sometimes also encounter technical problems. For example: the blade installed on the lathe tool follows closely and protrudes slightly than the blade for cutting. The purpose is to process good surface roughness of parts. Eccentric turning starts from the center of the rotating workpiece to ensure that the cutting edge cuts into the workpiece slowly.

First of all, the importance of cutting: cutting parts need to remove a lot of machining allowance, turning and milling machine processing should be the best choice. Discontinuous cutting: turning tool is usually not good for discontinuous cutting, but milling cutter can do it well. Milling is often defined as a kind of discontinuous cutting. Therefore, in the case of discontinuous cutting, it should be thought of turning to milling. Excellent chip breaking processing: over the years, machining practice has proved that for some equipment parts, milling instead of turning can eliminate the previous phenomenon of “bird’s nest” shaped chips entangled in the cutter head. Because the milling process with the advantage of natural chip breaking is combined in cutting, the continuous chips are broken into small pieces which are easy to be eliminated.

Flexible shaft machining: when turning long and thin parts which can not be supported in the middle, milling can prevent the parts from bending. Compared with turning, in theory, milling can cut parts under very small pressure. But in fact, a lot of technical problems need to be solved.

Continuous time processing: in the cutting of difficult to machine materials, the service life of a turning tool is very short, while the milling cutter can be used for a long time because it distributes the cutting load through multi edge cutting. Because the milling cutter has a long service life, it can save the trouble of changing the cutter many times during cutting. Eccentric processing or special-shaped processing: the radial (x-axis) movement of milling cutter can be consistent with the rotation movement of workpiece, and it has certain processing advantages to process the contour of complex parts.

The above is about the mechanical parts milling machine processing technical problems, thank you for sharing!

ken. tang@chengcg.com

CNC machining accuracy requirements

It can be said that the processing difficulty of automatic equipment parts completely depends on the dimensional accuracy of production drawings. General parts machining accuracy requirements have a lot of, the following understanding of machining accuracy requirements concept, let’s take a look

In the field of machining, the concept of dimensional accuracy requirements on production drawings can be divided into three categories. The first is the position accuracy. It refers to the conformity degree between the actual position and the ideal position of the point, line and surface in the machining of mechanical parts. According to GB / t1182-1996, there are 8 items to evaluate the position accuracy, including parallelism, perpendicularity, inclination, coaxiality, symmetry, position, circular run out and total run out. Position accuracy is controlled by position error, and the position tolerance of each item is divided into 12 Accuracy grades.

The second is dimensional accuracy: it refers to the degree that the actual value of dimensions such as diameter, length and surface distance of mechanical parts is close to the ideal value. Dimensional accuracy is controlled by dimensional tolerance. Dimensional tolerance is the allowable variation of part size in machining. When the basic dimensions are the same, the smaller the dimensional tolerance is, the higher the dimensional accuracy is. According to the national standard GB / t1800.2-1998, dimension tolerance is divided into 20 tolerance grades, namely IT01, it0, it1, it2, it17 and it18. It stands for standard tolerance (it is the abbreviation of international tolerance in English). The grade code of tolerance is expressed in Arabic numerals. From IT01 to it18, the accuracy decreases and the tolerance value increases in turn.

Finally is the shape accuracy: refers to the mechanical parts processing line, the surface actual shape and the ideal shape conformity degree. According to GB / t1182-1996, there are six items to evaluate the shape accuracy, including straightness, flatness, roundness, cylindricity, line profile and surface profile. Shape accuracy is controlled by shape tolerance. Except for roundness and cylindricity, all shape tolerances are divided into 12 precision grades. Grade 1 is the highest and grade 12 is the lowest.

The above is the requirement of machining accuracy. Thank you for sharing!

ken. tang@chengcg.com

Processing technology of common lathe

In the mechanical processing industry, ordinary lathe processing is mainly used to turn the rotating workpiece. It can also be processed with drill, reamer, reamer, tap, die and knurling tools. What is the processing technology of lathe processing in daily work? Let’s take a look at

In the machining process, in order to ensure the accuracy of each processing surface of the workpiece; During machining, the workpiece rotates around a fixed axis, and each surface has the same rotation axis, so it is easy to ensure the requirements of coaxiality between machining surfaces; The cutting process is stable; In addition to the intermittent surface, generally the lathe processing process is continuous, unlike milling and planing, in a process of cutting, the cutter teeth have multiple cuts in and out, resulting in impact; It is suitable for precision machining of nonferrous metal parts; Because of the low hardness and good plasticity of some non-ferrous metal parts, it is difficult to obtain a smooth surface by other processing methods; The cutting tool is simple; Turning tool is one of the simplest cutting tools. It is very convenient for manufacturing, grinding and installation, which is convenient for selecting reasonable processing technology according to specific processing requirements.

The above is the ordinary lathe processing technology, thank you for your attention.

ken. tang@chengcg.com

CNC processing cost accounting method

In the mechanical processing industry, consulting customers to understand whether the processing price of mechanical parts is reasonable, first of all, they need to calculate the processing cost and provide the quotation of mechanical parts processing, which refers to the amount of object-oriented calculation at the expense of various economic resources in the operation process of mechanical processing manufacturers. Generally speaking, it refers to the total cost of producing, processing and selling a certain product.

How to calculate the processing cost of mechanical parts, first understand the weight of raw materials, and then multiply the price equal to the material cost. Then through the different machining process, the processing time needed to calculate the processing cost. If the mechanical parts have surface treatment processing technology, processing surface treatment fee. See if the customer wants to include tax, and finally increase the tax point. This is the process of calculating the processing cost of mechanical parts!

There are also detailed steps to calculate the processing cost of mechanical parts, mainly including raw material cost + CNC processing cost + milling machine processing cost + lathe processing cost + grinder processing cost + wire cutting processing cost + fitter cost + surface treatment cost + tax + packaging cost, etc. according to the different processing technology of mechanical parts, the processing price of mechanical parts is finally obtained. That is the cost of machining!

ken. tang@chengcg.com

CNC machining center bearing maintenance

In the field of mechanical processing industry, CNC machining center is also known as computer gong processing. Nowadays, the accuracy requirements of automatic equipment parts processing, fixture design and manufacturing are higher and higher. In order to improve the production quality, exquisite technology and daily maintenance of mechanical processing equipment are very important. For example, in the process of CNC machining, to maintain the best state of machining performance and extend the service life of machine tool bearings, we must know the daily maintenance of CNC machining center bearings. The following is the daily maintenance method!

When the CNC machining center machine tool works for a long time, remove the bearing regularly and put it into gasoline for cleaning to wipe off the oil sludge and dust left on the bearing. All the rusty bearings are gently polished with metallographic sandpaper until there is no roughness by hand; Wipe the cleaned bearing dry with dry rag, and then soak it in antirust oil. In this process, the bearing should be completely contacted with the antirust oil, and the bearing should be rotated continuously, so that the oil film formed by the antirust oil can cover the surface of the bearing and achieve the purpose of antirust; Next, apply lithium grease and grease evenly on the surface of bearing, including inner and outer rings, wheels and cages. And it turns the bearing while wiping, so that the grease really enters into the bearing and plays a full lubricating role.

The above is the CNC machining center daily bearing maintenance method, thank you for sharing!

ken. tang@chengcg.com

POM saigang has a variety of colors

In the field of mechanical processing, we often come into contact with 45 ° steel, stainless steel 303304, brass, aluminum alloy and other metal materials. Generally, parts and accessories of automation equipment are used more, such as plastic nylon, peek, ESD, POM saigang and other materials, mainly in the production of fixture and fixture, and parts and accessories of mobile phone automation equipment. Because the density of plastic is small, the weight of fixture design needs to be light. According to the requirements of the design engineer, different machining materials or material appearance colors can be selected. For example: choose the color of plastic POM match steel, let’s see how many colors there are in the machining material POM match

People who have just come into contact with machining think that POM saigang should be a metal material. There is a steel character in the name. In fact, it is wrong to understand it in this way. POM saigang is a kind of plastic with low material density. It is very suitable for the production of fixture. The common colors are white and black. There are seven colors of POM saigang, including white, black, yellow, red, green and blue. In the process of machining mechanical parts, white and black are most used in automation equipment and fixture.

There are also several other colors, which can also be used according to the appearance requirements of design engineers. In the machining industry, the above are several colors of POM saigang materials. If customers have special requirements for colors, they can also make different colors according to customers’ requirements.

ken. tang@chengcg.com

CNC processing method of nylon material

In the field of machining, different materials are processed by different processes. Now, the processing method of lower plastic nylon material is discussed. Nylon material belongs to plastic. When machining a hole with a diameter less than 30mm, due to the narrow space in the hole and the difficulty in heat dissipation, the lathe speed should be reduced to less than 300rpm to cool it with cutting fluid; Slow and uniform drilling and timely chip removal; When the drill is about to penetrate through the hole bottom, more care should be taken to reduce the drilling speed. Cutting fluid or cooling water must be evenly sprayed to the hole.

Secondly, when nylon material is used to machine holes larger than 30mm in diameter, the drill should be sharpened to facilitate processing and avoid damage to the workpiece; If the lathe speed is lower than 180 rpm, the lathe speed can be reduced to about 60 rpm if the hole is larger than 55mm; Slow and uniform drilling, timely chip removal, spraying sufficient cutting fluid; When drilling out, be careful about the speed of drilling back. When the lathe processes small diameter hole, the speed should be lower than 60 rpm; When drilling at a constant and low speed, the operator must hold the tailstock handle firmly to prevent the drill bit from being brought into the hole quickly by the lathe and causing the product to crack; The cutting fluid is sprayed evenly.

For nylon material cylindrical processing, white steel tool is better to be used than alloy tool, and the tool should be kept sharp; The lathe speed shall not be less than 200 rpm; Proper feed speed can improve machining accuracy and surface finish.

The above is a brief introduction to the processing methods of plastic nylon materials by mechanical processing manufacturers. Thank you for your attention.

ken. tang@chengcg.com

Author Archive chengcg

CNC machining raw material cutting grade

Introduction of CNC milling cutter

Introduction of CNC parts processing fixture

Technical problems of milling machine

CNC machining accuracy requirements

Processing technology of common lathe

CNC processing cost accounting method

CNC machining center bearing maintenance

POM saigang has a variety of colors

CNC processing method of nylon material

CNC Machining parts

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