Monthly Archive June 8, 2021

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

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

Causes of chromium plating rust on 45 steel

45 ᦇ why will steel rust after chrome plating? In fact, steel chrome plating will not rust, if there is rust, there must be a reason, let’s take a look

In the process of machining mechanical parts, there are several reasons for parts to rust after chrome plating,

  1. If the parts are not thrown to the position during chrome plating, the chrome plating chemical solution can not hold the surface of the parts, and it will rust after a period of use;
  2. The time for mechanical parts to be put in the liquid medicine is not enough, so that the chromium plating layer on the surface is thin, and the surface will rust in the process of mechanical parts assembly;
  3. When the surface is treated with chromium plating, the temperature of the liquid medicine is not enough to make the machined parts fail to meet the treatment requirements, and it will be easy to rust later! This is also caused by incorrect surface treatment and process of chromium plating.

The above is the reason why the chromium plating treatment of 45 steel will rust. Thank you for sharing!

ken. tang@chengcg.com

CNC machining inspection process

High quality comes from exquisite technology! Before the precision CNC machining of general mechanical parts and automatic equipment accessories, we must see clearly the contents of the machining process card, the parts to be machined, the shapes, the dimensions of the drawings, and the processing contents of the next process. It is also the self checking process of precision machining!

Attention should also be paid to the self inspection of precision CNC machining: before the workpiece is clamped, the blank size should be measured to see if it meets the requirements of the drawing. When the workpiece is clamped, it must be carefully checked whether its placement is consistent with the programming operation instruction; After rough machining, self inspection should be carried out in time to adjust the data with errors in time. The main content of self inspection is the position and size of the processing part.

Whether the machined parts are loose or not; Whether the workpiece is correctly divided into parts; Whether the dimension from the machining part to the datum edge (datum point) of precision CNC machining meets the drawing requirements; The position and size of machining parts. After checking the position and size, measure the rough machined shape ruler (except arc). These are the basic contents of self inspection!

Many years of precision CNC processing factory conclusion, after rough machining self-test before finishing. After finishing, the workers should check the shape and size of the processing parts: check the basic length and width of the processing parts on the vertical plane; Measure the base point size marked on the drawing for the machining part of the inclined plane. The operator can remove the workpiece and send it to the inspector for special inspection after completing the self inspection of the workpiece and confirming that it conforms to the drawing and process requirements.

The above is about the self inspection process of precision CNC machining manufacturers. Thank you for sharing!

ken. tang@chengcg.com

Classification of CNC lathe processing

In the field of machining, the raw materials are clamped for rotary motion, and the turning tool is used for radial or axial machining, which is called lathe machining. In the field of hardware mechanical parts processing industry, lathe processing equipment is classified as: automatic lathe, ordinary lathe, numerical control lathe and instrument lathe. For different mechanical parts processing, hardware parts processing and other requirements, the selection of suitable processing equipment can reflect the unique advantages of the equipment!

Lathe processing equipment such as automatic lathe: the main object of batch hardware parts processing, no special precision requirements; Ordinary lathe: for automatic mechanical equipment parts shaft, rod, non-standard screw processing, suitable for single or small batch parts processing; CNC lathe: for batch hardware mechanical parts processing, high precision is guaranteed; Instrument lathe: mainly for micro mechanical parts processing, on the ordinary desktop can operate.

The general understanding of hardware refers to the combination of gold, silver, copper, iron and tin; Hardware mainly includes coated plate (such as white iron sheet), coated wire (such as iron wire), various small standard parts (such as fastening screws), non-standard parts (such as wood screws) and various small tools (such as screwdrivers); Hardware generally refers to metal plate, pipe, profile, bar and wire.

The above is the classification of lathe machining, thank you for your attention!

ken. tang@chengcg.com

Difficulties and methods of CNC machining

In the field of machining, different parts of the processing complexity, need to choose different processing technology to complete. In the process of precision CNC machining, we will encounter various parts processing, some parts are complex, we need to find the appropriate processing technology, which is often said to be the best way. Let’s take a look at the methods and difficulties in the process of precision CNC machining?

The first is precision CNC machining method, which includes cutting, abrasive machining, non-traditional machining and compound machining; According to the mechanism and characteristics of machining methods, it can be divided into three categories: removal machining, combination machining and deformation machining. At present, the traditional machining methods represented by cutting, grinding and polishing still occupy the main position.

The third is the difficulty: in the process of precision CNC machining,

① Ultra micro machining is just like cutting discontinuity, so the stress is difficult to remove;

② The stiffness and thermal deformation of the process system are large, which have great influence on the machining accuracy;

③ The micro deformation of tool and workpiece surface is random,

It is difficult to control the precision

① Precision machining mechanism;

② Precision processing equipment;

③ Precision machining tools;

④ Workpiece material;

⑤ Precision measurement and error compensation technology;

⑥ Working environment, conditions, etc.

The above are the methods and difficulties in the process of precision CNC machining!, Thank you for your attention!

ken. tang@chengcg.com