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Precision CNC machining criteria

CNC machining can change the shape and size of products, which plays a very important role.

Many friends do not understand the high-speed CNC machining process benchmark.

The broad meaning of benchmark is the meaning of “basis”. In mechanical manufacturing, the datum refers to the points, lines and surfaces used to determine the geometric relationship between geometric elements on the production object. According to the different functions and applications, the datum can be divided into two categories: design datum and process datum. Process datum can be divided into process datum, locating datum, measuring datum and assembling datum.

High speed CNC machining technology is the premise to ensure the production of high-quality parts.

On the lathe, the shape and size of the blank can be changed by the rotary motion of the workpiece and the linear or curvilinear motion of the cutter, so that it can be processed to meet the requirements of the drawing.

Ordinary machine tools are more and more difficult to meet the needs of machining precision parts,

At the same time, due to the improvement of production level, the price of CNC machine tools is falling from time to time. CNC precision parts processing mainly includes ultra precision turning, mirror grinding and grinding.

The primary premise of CNC precision parts processing is the accuracy of process datum. The datum on mechanical drawings are all represented by capital letters a, B, C, D, etc. with a specific ring datum symbol. When the datum symbols are aligned with the surface and the extension line of the surface or the dimension limit of the surface, the indication is based on the surface. When the datum symbol is aligned with the dimension line, it is indicated that it is based on the solid center line of the dimension. It is a more general statement that the accuracy of the technology mentioned above is mentioned for you.

Assembly benchmark refers to the accuracy of the position of parts in parts or products during assembly. Measurement benchmark refers to the specification for the size and position of the measured processing surface when the parts are inspected. Positioning reference, refers to the processing, the workpiece in the machine tool or fixture positioning with the reference.

Polishing and grinding of hardware electroplated parts

For hardware electroplated parts, grinding and polishing is a very important step. Polishing technology and polishing effect are directly related to the smoothness, roundness, porosity and brightness of electroplated coatings. Especially for the products with high surface finish, it has strict requirements for the proficiency of polishing machine, grinding wheel, polishing wax, polishing workers and inspectors.

There are polishing lines for plastic electroplated parts, copper parts and aluminum alloy parts. The polishing methods and process details of different electroplating products are very different. It needs to adopt different polishing methods for different product data, different polishing wheels, different polishing wax and wheel rotation speed, so as to obtain high plating product rate and plating layer quality.

Even if it is the same kind of material Hardware electroplating parts polishing, is not the same situation, not the same treatment. There are red copper parts, brass parts, bronze parts, stamping parts, copper casting parts and turning parts. Although they are all copper parts, their polishing methods are different.

For example, the material of the copper stamping parts is generally better, so it is better to polish the surface of the copper stamping parts, The earliest use of 320 mm or 400 mm abrasive belt grinding once, if it is a high demand mirror, then use 600 mm abrasive belt to play once, then use 25 mm hemp wheel to hit diamond white wax, and finally polish with polishing powder. Maybe use soft cloth wheel to hit Japanese white wax or green wax or OK, if it is the demand for high mirror surface, use wool wheel to hit Japanese white wax. Here, pay attention to the soft and hard hemp wheel will directly affect the oil skid of the product.

For the surface polishing of hardware electroplated parts, it is often divided into rough polishing, medium polishing, fine polishing, ultra precision polishing and super mirror polishing. In order to achieve the corresponding surface effect, what type of polishing wheel is selected? What are the characteristics of polishing wax? What kind of process parameters and process flow can be used to obtain the most useful electroplating effect with the lowest polishing cost, which is the main content of electroplated parts polishing technology.

There are many types of manual polishing machine and active polishing machine on the market. Active polishing machines such as disc polishing machine, reciprocating plane linear polishing machine, aluminum plate stainless steel plate double axis polishing machine, pipe polishing machine, etc. At present, there are more advanced active polishing equipment operated by manipulator and robot. In active polishing machine, liquid wax and special polishing wax are usually used for polishing.

The main data of the manual polishing machine are polishing wax and polishing wheel.

According to the abrasives contained in polishing wax, they can be divided into four categories

1, diatomite 2, quartz powder 3, alumina 4, chromium oxide

According to the function of polishing wax, it can be divided into five types: coarse polishing wax, medium polishing wax, fine polishing wax, super polishing wax and super mirror polishing wax.

We also used to use color to distinguish polishing wax, also known as yellow wax, purple wax, green wax, small white wax, etc.

Because of the different sizes and colors, there are no uniform sizes and colors on the market.

For example, stainless steel polishing wax is used to: palmitic acid, stearic acid, rosin adhesive, plus abrasive feldspar powder, corundum, chromium oxide, iron red, etc., and then according to different matrix composition and requirements, different fineness and varieties are made.

Therefore, how to select the appropriate polishing wax is an important step in the polishing and polishing of metal electroplating parts.

In addition to the specifications and dimensions, such as internal and external diameter, thickness, number of layers, maximum speed and rotation direction, the polishing wheels can be divided into the following categories according to their data and shapes:

Cloth wheel

It is made of cotton cloth, white cloth, denim, colored miscellaneous cloth, etc.

The structure shape of cloth wheel includes wave type, fold type, finger type, etc. In addition, there are wind cloth wheel, plane denim cloth wheel, plane color cloth wheel, button cloth wheel, bag cloth wheel and so on.

Hemp wheel

The hemp wheel is made of linen.

Its structural shapes are: plain pure hemp wheel, twill hemp wheel, U-wave hemp wheel, wavy hemp wheel, folded hemp wheel, wind hemp wheel, finger hemp wheel, plane cloth folder hemp wheel, fiber hemp wheel, group nail hemp wheel, etc

Hemp rope wheel

It’s made of hemp rope. There are hemp rope wheel, hemp rope wind wheel, steel core hemp rope wheel, etc.

Nonwoven wheel

Not only cloth wheel is made of different abrasives, man-made fibers and adhesives, but also called nylon wheel. It has nylon wheel, nylon wind wheel, various special-shaped nylon wheel.

At present, there are more businesses using alumina, silicon carbide and other abrasives and a variety of special fibers made of non-woven cloth polishing wheel, this kind of polishing wheel is suitable for the polishing and polishing of various surfaces of objects.

Chip removal of computer gongs

It is said that the chip forming device with positive rake angle on the blade can reduce the cutting force and reduce the cutting power consumption by 15% – 25%. It can also guide the chip to leave the cutting area, so as to prevent the side of the machined part from being scratched by the chip. The chip is guided to flow inward (tool center) rather than outward (workpiece sidewall). The tool is equipped with two types of blades, one is used for slotting and the other is for cutting.

Tanglot milling cutter can be supplied as FDN flange type or SDN disc type cutter. The tool width can be adjusted according to the tool collet used and the blades with different widths. The range of tool diameter is 100-250mm, and the width of tool is 6.0-14.6mm. The new tool can be used for grooving and cutting of automobile bearing cover, steering knuckle and connecting rod, as well as other conventional slotting.

(2) Seco tools Inc. claims its new crown MF5 chip breaker has increased tool life by 67% in field cutting tests and improved chip control in 41% of tests. According to the company, MF5 chip breaker is optimized for semi finish machining related to near net machining. Its chip breaking groove can generate very small cutting force and allow the tool to carry out advanced cutting at a cutting depth of 0.5-2.7mm. MF5 chip breaker adopts crown shape with three sharp forks, chip guiding platform and cooling channel, which is conducive to small deep cutting and ultra-high pressure cooling. In addition, the open geometry angle can reduce the cutting force. The chip breaker has a ground island shaped protuberance, which can improve the positioning of the blade and is conducive to the heat dissipation of the workpiece and cutting edge.

MF5 chip breaker is used in 8 kinds of positive C-type and standard W-type blades (brand numbers are TK1000, tk2000, tp1000, tp3000 and duratomic tp2500). When roughing the steel rock bit (hardness hrc42 ～ 45), the tool life of TK1000 made of MF5 chip breaker is 5 times longer than that of a competitive chip breaker. In the similar cutting experiment with MF5 tp2500 blade, compared with tp2000 blade with M5 chip breaker, the productivity is increased by 55% and the tool life is increased by 360%.

(3) Sandvik Coromant’s new LC blade geometry prevents chip clogging that often occurs when cutting difficult to machine materials. Because of the edge shape design of LC blade, the risk of chip accumulation in machining low carbon steel workpiece is reduced, so the tool life and machining surface finish are improved. The scraping edge can increase the feed rate. The company provides LC turning blade grades for low carbon steel machining, including gc4225, gc1525 and gc2025.

(4) It is designed by guhring-48, Inc., which is easy to produce fine cutting chips. The 3365 series allows slotting and rough milling of steel parts at high cutting speeds and feed rates, while achieving maximum metal removal with minimum torque horsepower, the company said. The milling cutter is also suitable for machining titanium and titanium alloy aviation materials and nickel base alloy.

Cobalt collar has also launched 3376 series aluitech LR and 3364 series roughtech Alu three groove carbide end mills for processing aluminum and aluminum alloys. The above three kinds of end milling cutter series are supplied according to the standard specifications, and the cutter diameter ranges from 6.0 mm to 20.0 mm.

Mainly engaged in a variety of plastic mold design, manufacturing and plastic products injection, injection, pad printing and other processing services. The company produces a wide range of mold types, including various household appliances, computer weekly products, communication products, power tools and CD, DVD, MP3, MP4 categories, etc., which can be used to make rapid template mold and two-color molding mold. It can take into account large, medium and small die. The largest mold size is 2 m * 1 m, and the maximum weight can reach 8 tons.

Reasons for uneven machining of CNC parts

In the process of using computer gong machining center, the tool imbalance may appear. If not adjusted in time, it will affect the processing effect. Therefore, we should always pay attention to the tool balance of the computer gong machining center. What are the main reasons for the imbalance of the handle?

The main reasons are that the design of the tool is asymmetric, there are defects in the tool body, and all the adjustments on the tool. The correct balance of the tool can significantly reduce noise and vibration, which increases the tool life and improves the accuracy consistency of parts.

The centrifugal force of computer gong machining center magnifies the vibration caused by unbalance in proportion to the square of velocity. The vibration increase of CNC machining center caused by the machining center minimizes the service life of bearing bush, bearing, shaft, spindle and gear.

It is necessary to measure the magnitude of the unbalance and the angle position of each selected correction plane before balancing the tool on the computer gong machining center. These variables are measured on two general types of balancing machines: non rotating or gravity machines are used to measure single plane unbalance, while rotary or centrifuge is used to measure single plane or two plane unbalance.

After measuring the magnitude and angle of the unbalance in the correct plane, you can correct it by adding or removing material from the workpiece. For the components which are not tools, the most widely used material adding method of drilling center is welding counterweight on the components.

For components with slight unbalance, other methods include adding solder on the assembly body or increasing weight in pre drilling. For tools, when you determine that the unbalance must be removed in order to get the correct balance, the easiest and most effective method is drilling.

Check the condition of lubrication system and pressure gauge, clean the filter screen of lubrication system, change lubricating oil and dredge oil circuit. machining center
Check the gas system, clean the air filter screen and eliminate the leakage of pressure gas.
Check the fluid system, clean the filter, clean the oil tank, replace or filter the oil. If possible, replace the seal.
Fasten the transmission parts and replace the defective standard parts.
Grease lubrication parts, according to the requirements, add grease
Clean and clean all driving surfaces,
Check the status of tool magazine and manipulator for computer gong processing, analyze the wear status of manipulator, and propose replacement suggestions to customers.
Repair and repair the damaged parts of external components.
Check the condition of the protective cover.

Honing of parts processing

Honing is a machining method that uses a group of diamond (or cubic boron nitride) honing heads with different diameters according to the size order, and each grinding head only makes one reciprocating cutting action in turn. After all the honing heads are machined, the final part requirements are met. The sequential honing technology is developed on the basis of traditional honing, which combines honing method with reaming method, so it is also called honing; in addition, sequential honing generally only has one reciprocating action, so it is also called single stroke honing

The characteristics of sequential honing mainly lie in its sequential honing head and actual honing process. Compared with the traditional honing process, the honing head of sequential honing has been set to the final machining size required by the workpiece in advance. Therefore, the cutting process of sequential honing only needs 1-3 reciprocating strokes. The thickness of metal layer removed by each honing head is 2-20 μ M. The shape and dimension accuracy of the hole can be improved by one level after the sequential honing, and the surface roughness value can reach Ra0.2. This processing method does not need tool feed, the processing time is fast, and also can improve the position accuracy of the hole to a certain extent.

Compared with ordinary honing machine, sequential honing machine has some advantages in processing beat, dimensional stability, shape and position accuracy. However, the domestic users of this honing machine tool used to rely entirely on imports. Because of the high price of machine tools, machine accessories and after-sales service, many users are deterred from importing sequential honing machines. The users who have the ability to purchase imported sequential honing machines also affect their production due to the lack of timely technical support from imported machine tools. Until the beginning of 2008, the third machine tool branch of Beijing No. Compared with foreign manufacturers which have developed for many years, they started later, but started higher. The sequential honing machine tools produced by them have been favored by many users as soon as they come into being, and have achieved multiple sales.

The machine tools they produce adopt German Siemens Servo motor and 810D numerical control system to realize the flexible adjustment of reciprocating speed and position, realize the real-time detection of processing torque of each processing shaft and set overload alarm; adopt German fibro rotary table, which has accurate positioning and fast speed, and the transposition time of each station reaches 0.69s; the rolling guide rail and ball screw of Japan THK can realize this At present, the spindle box is stable and accurate reciprocating; the honing tool, tool extension rod and workpiece fixture are all of full floating structure, which can ensure high honing accuracy: roundness: 0.001 mm, cylindricity: 0.002 mm, roughness: Ra0.2 μ m; processing beat is 9s / piece. Their machine tool also adopts modular design, and the number of spindles and turntable stations can provide users with the best processing scheme according to the process requirements of users and their parts. In recent years, with the batch launch of domestic medium-sized CNC machine tools, some high-end CNC machine tools began to enter the core manufacturing field of key industries, and were initially applied.

At the high-level forum of CNC machine tool exhibition, the equipment utilization rate of similar imported machine tools was 89.5%, and the domestic equipment was basically close to the same level of foreign equipment. “

As the user side of domestic CNC machine tools, the main problems of domestic CNC machine tools are the lack of design and innovation ability, slow response speed, no serial and high maturity CNC system, the quality of accessories needs to be improved, and the overall service awareness is weak.

According to the special plan for high-end CNC machine tools and basic manufacturing equipment, by 2020, about 80% of the high-end CNC machine tools and basic manufacturing equipment required by aerospace, shipbuilding, automobile and power generation equipment manufacturing will be based in China, which requires the industry to focus on the automobile, machinery manufacturing, military and other key downstream industries.

Experts suggest that the machine tool industry in the “Twelfth Five Year Plan” period should develop high-end market segments, focus on the product and process requirements of high-end customers and major customers, and provide personalized services according to the needs of customers. At the same time, we should closely track the development of strategic emerging industries and provide them with advanced and applicable machine tools and equipment.

Methods of quality inspection

Seven new methods of QC

① Relation graph method (association graph method);

② KJ method (affinity graph method, card method);

③ System diagram method (tree diagram method);

④ Matrix diagram method;

⑤ Matrix data analysis method;

⑥ Process decision program chart (PDPC)

Or major accident prediction chart method;

⑦ Network graph method (also known as network planning technology < PERT > method or vector diagram is also called critical path

Line method)

Five core manuals of ISO / TS16949

① FMEA (potential failure mode and effect analysis)

mode and effects Analysis）；

② MSA (measurement system analysis);

③ SPC (statistical process control);

④ APQP (advanced product quality planning and control plan)

Product Quality Planning (APQP) and Control Plan)；

⑤ PPAP (production part approval process)

The most important of the five manuals is APQP

10s / five constant method

（1） 10s from 5S

1s: finishing (Seiri)

2S: Seiton

3S: cleaning (seis0),

4S: cleaning (seiketsi)

5S: accomplishment (shitsijke)

6S: Safety

7S: saving / speed

8s: Service (servlce)

9s: satisficatl0n

10s: persistence

Five regular methods

The five constant method is a technology used to maintain the quality environment, which is called 5S in western countries. Hong Kong is known as the “five constant laws”. Due to the language needs, it has translated five English words, namely, structure, systematise, sanitise, standardization and self discipline. The implementation of the five standing laws in Hong Kong naturally requires the cooperation of five Chinese characters. It is also what we usually say: sorting out, rectifying, cleaning, and self-cultivation.

Chinese * English (5-s) * 50 points * court example*

① Often organize structurise 10 to throw away or return unnecessary items

② The file can be found in 30 seconds after regular systematise rectification

③ 5 people should be aware of hygiene responsibility

④ Storage transparency of standard 15;

⑤ Self discipline 10 daily use of five

Dry, semi dry and low temperature cold air cutting technology

In the process of cutting, elastic deformation, plastic deformation and friction deformation occur in the three deformation zones, 99.5% of the cutting power is transformed into shear slip deformation (the first deformation zone), the friction deformation of the rake face (the second deformation zone), and the energy consumed by extrusion, excess deformation and friction deformation of the back face (the third deformation zone), and it is transformed into heat energy in an instant, resulting in the temperature rise of chip, cutting edge area and workpiece surface.

Cutting heat is an inevitable physical phenomenon in the process of metal cutting, which has a significant impact on the quality of workpiece and tool life. In low-speed cutting, mechanical wear is the main reason for tool wear; while in high-speed cutting, high-temperature induced tool wear changes from mechanical wear to diffusion wear, phase change wear and carbonization wear, and leads to adhesive wear on the tool surface. Cutting heat also causes the thermal expansion of cutting tools and workpieces, aggravates the friction and wear of the flank of the cutting tool, and causes the surface roughness of the workpiece to rise. Therefore, the ultra precision machining process emphasizes that the conduction of cutting heat in the workpiece and tool must be controlled timely and effectively. It is also very important to control the temperature rise of tool and workpiece for NC machining.

The cutting heat of metal originates from the strength, hardness, toughness, plasticity and elasticity of materials. The research also shows that the temperature rise of cutting tool and workpiece is closely related to the contact area, heat transfer coefficient, temperature difference, contact time and so on. Generally speaking, reducing the cutting rate can reduce the contact area between the tool and the heat source; increasing the flow rate and flow rate of the cooling medium is to increase the heat transfer coefficient; reducing the temperature of the cooling medium can increase the heat capacity and temperature difference effect of the cutting tool and workpiece; and increasing the machine speed and cutting speed actually shortens the heat conduction time of cutting.

It can be seen that in order to control the cutting heat of metal and the temperature rise of cutting tools and workpieces, various factors must be considered comprehensively. In addition to the reasonable selection of cutting tools and cutting process parameters according to the characteristics of metal materials and machining technical indicators, the most direct measure is to use various cooling media to quickly take away the cutting heat on the tool and workpiece and reduce the temperature.

CNC cutting technology

When high speed milling is used to finish hardened die steel, one of the main factors to be observed is to use shallow cutting. The cutting depth shall not exceed 0.2/0.2 mm (AP / AE: axial cutting depth / radial cutting depth). This is to avoid excessive bending of the toolholder / cutting tool and to keep the machined die with small tolerance and high accuracy.

It is also important to choose a clamping system and tool with good rigidity. When using monolithic cemented carbide tools, it is very important to use tools with the largest core diameter (maximum bending rigidity). A rule of thumb is that if you increase the diameter of the tool by 20%, for example from 10 mm to 12 mm, the bending of the tool will be reduced by 50%. It can also be said that if the tool overhang / extension is shortened by 20%, the tool bending will be reduced by 50%. The tool holder with large diameter and taper further improves the stiffness. When ball end mills with indexable inserts are used (see mold manufacturing sample c-1102:1), if the handle is made of integral cemented carbide, the bending rigidity can be increased by 3-4 times.

When high speed milling is used to finish the hardened die steel, it is also very important to select the special groove and grade. It is also important to select coatings with high thermal hardness such as TiAlN.

11) When should forward milling be used and when should reverse milling be used?

The main suggestion is: use down milling as much as possible.

When the cutting edge is just cutting, the chip thickness can reach its maximum value in down milling. In the reverse milling, it is the minimum value. Generally speaking, the tool life in up milling is shorter than that in down milling because the heat generated in up milling is significantly higher than that in down milling. When chip thickness increases from zero to maximum in up milling, more heat will be generated because the friction of cutting edge is stronger than that in down milling. The radial force is also obviously high in up milling, which has a negative effect on the spindle bearing.

In down milling, the cutting edge is mainly subjected to compressive stress, which is much better than the pulling force produced in up milling on cemented carbide blade or integral carbide tool. There are exceptions, of course. When using solid carbide end mills (see tools in die sample c-1102:1) for side milling (finish machining), especially in hardened materials, the top milling is preferred. It’s easier to get a better straightness and a smaller wall angle of 90. If there is no coincidence between different axial feed, the tool mark is also very small. This is mainly due to the direction of the cutting force. If a very sharp cutting edge is used in cutting, the cutting force tends to “pull” the knife toward the material. Another example that can be used for up milling is the use of an old manual milling machine, which has large lead screw clearance. Up milling produces cutting force to eliminate clearance, which makes milling action more stable.

12) Profile milling or contour cutting?

In cavity milling, the best way to ensure the success of down milling tool path is to use contour milling path. Milling the outer circle of a milling cutter (e.g. ball end mill, see die manufacturing sample c-1102:1) along contour lines often yields high productivity because more teeth are being cut on larger tool diameters. If the speed of the machine spindle is limited, contour milling will help to maintain the cutting speed and feed rate. With this tool path, the change of working load and direction is also small. This is particularly important in high-speed milling applications and hardened material processing. This is because if the cutting speed and feed rate are high, the cutting edge and cutting process will be more vulnerable to the adverse effects of working load and direction changes, which will cause changes in cutting force and tool bending. Profiling milling along the steep wall should be avoided as far as possible. The chip thickness is large at low cutting speed when profile milling is carried out. In the center of the ball knife, there is also the danger of breaking the edge. If the control is poor, or the machine tool has no pre reading function, it can not decelerate fast enough, and it is most likely to cause the edge breakage in the center. The reason is that the chip thickness is the maximum under the favorable chip speed.

In order to obtain the longest tool life, the cutting edge should be kept continuous cutting as long as possible in the milling process. If the tool enters and exits too frequently, the tool life will be significantly shortened. This will aggravate the thermal stress and thermal fatigue on the cutting edge. It is more advantageous for modern cemented carbide tools to have uniform and high temperature in the cutting area than large fluctuation. Profiling milling path is often a mixture of up milling and down milling (zigzag), which means that the cutter will be frequently fed and withdrawn during cutting. This kind of tool path also has bad effect on the quality of die. Every time you eat a knife, it means that the tool is bent, and there is a mark of lifting on the surface. When the tool exits, the cutting force and tool bending decrease, and there will be a slight “over cutting” of the material in the exit part.

PMM alarm of computer gong machining center system

If there is no emergency stop and alarm, the alarm will be sent out if there is no emergency stop and alarm. Therefore, all channels of the above CNC machining center are fault points.

Check whether the plugs of CNC machining center are in poor contact, including command line and feedback line.
Check whether the LED has display, if not, it is the board is not powered on or the power circuit is broken.
Check whether the AC voltage of external CNC machining center is normal.
Check whether the DC voltage on the control board is normal. If there is any abnormality, the CNC machining center shall check whether the fuse on the board and the power circuit on the board are burnt out. If it cannot be repaired by itself, replace the amplifier or send it back to the manufacturer for repair.
Carefully observe whether the green light of pay in CNC machining center turns on and off, or it doesn’t pull in at all. If it is closed and then disconnected, it may be that the contact of the relay is not good. Replace the relay. If it is a working environment with woodworking machinery or dust, it can be basically judged that the contact of the relay is not good. If it doesn’t pull in at all, the relay coil of the unit is not good or the control board is not good or there is a broken line, which can be judged by measuring the coil resistance of the relay.

How to deal with scratches after machining holes in computer gong machining center

See if you can change the next processing parameters, it may be unreasonable to set the parameters.
On the other hand, the effective way to avoid scratch is to use boring instead of drilling, and the process selection is wrong.
First of all, you need to see the processing drawing to know that if the thickness of the workpiece processed by the CNC machining center is not very thick, reamer can be used.
It’s also possible that your coolant water speed is slow and the amount of water is not enough, and the chips can’t be discharged.
CNC machining bit angle grinding point, and your penetration rate is too high

CNC machining operation language

1) Computer numerical control (CNC) uses computer to control processing function to realize numerical control. 2) Axis (axis) the reference direction along which parts of a machine tool can move in a straight line or in a rotary motion. 3) The machine coordinate system is a Cartesian coordinate system fixed on the machine tool and based on the zero point of the machine tool. 4) The machine coordinate origin is the origin of the machine coordinate system. 5) The workpiece coordinate system is a Cartesian coordinate system fixed on the workpiece. 6) The origin of the workpiece coordinate system. 7) Machine zero is defined by the machine manufacturer. 8) A fixed point along the coordinate axis used for starting a machine tool. It can use the origin of the machine coordinate as the reference datum. 9) The straight line distance or angle between absolute dimension / absolute coordinates and the origin of a coordinate system. 10) Incremental dimension / incremental coordinates the distance or angle between each point and the previous point in the increment of a sequence of points. 11) Minimum input increment is the smallest increment unit that can be input in the processing program. 12) Minimum command increment is the minimum increment unit of the coordinate axis movement of the command issued by the numerical control device. 13) Interpolation is the operation process of determining the position coordinates of multiple intermediate points between two known points on the required path or contour line according to a certain mathematical function (such as line, arc or higher-order function). 14) This is an interpolation method. In this way, the interpolation between two points is approached along the point group of the line, and the motion of the tool is controlled along this line. 15) Circular interpolation (Circular: interpolation) this is an interpolation method. In this way, according to the interpolation digital information between the two ends, the point group approaching the actual arc is calculated, and the tool movement along these points is controlled to process the arc curve. 16) The tool reference point of clockwise arc is a path formed by rotating the tool reference point around the track center and rotating in the negative angle direction. 17) the tool reference point of counter clockwise arc rotates around the track center and rotates in the positive angle direction. 18) Manual part progranmiog (manual part progranmiog) is used to make the part processing program manually. 19) Computer part prograrrnrnlng (computer part prograrrnrnlng) uses a computer and appropriate general processing program and post-processing program to prepare the part program and obtain the processing program. 20) Absolute prograrming is programmed with control words representing absolute dimensions. 21) increment programming uses the control word representing the increment size to program. 22) a set of element symbols used to represent an organization or control of data. 23) the control character appears in the specific information text and represents the character of a certain control function. Address a character or group of characters at the beginning of a control word to identify data that follows. 25) block format the arrangement of words, characters and data in a block. 26) instruction code / machine code computer instruction code, machine language, used to represent the instructions in the instruction set. 27) program number is the number assigned at the front end of each program when the program is identified by a number. 28) program name is the name assigned to each program when the program is identified by its name. Command mode. 31) part program is a sequential instruction set written in a certain language or format in order to make automatic operation effective. Part program is written on the input medium processing program, can also be prepared for the computer input, after processing to get the processing program. In the automatic machining control system, a sequential instruction set written in automatic control language and format. These instructions are recorded on the appropriate input medium and can be operated directly. 33) end of program refers to the auxiliary function for the end of workpiece processing 34) the auxiliary function that makes the spindle function and other functions (such as cooling function) be deleted after all commands in the end of data program section are executed. After all the commands of progrm stop program section are executed, the spindle function and other functions are deleted, and the subsequent auxiliary functions of data processing are terminated. 36) preparatory function is a command that enables the machine tool or control system to establish a machining function mode. 37) miscellaneus A command that controls the switching function of a machine tool or system. 38) tool function