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CNC Machining Center


February 7, 2017 Facebook Twitter LinkedIn Google+ CNC Machine



Computerized Numerical Control Machine (cnc) is a high-efficiency automatic machine tool composed of mechanical equipment and numerical control system for processing complex shape workpiece.

Table of content

1.Overview

2. Use

3. History of development

4. Classification / machining center

5. Composition / machining center

6. Advantages

7. Maintain

8. Maintenance methods

9. Safety rules

10.Other references

11.List of CNC Machining Center manufacturers

Vertical machining center_centro mecanizado vertical_FagorAutomation

1.Overview

Computerized Numerical Control Machine (cnc) is a high-efficiency automatic machine tool composed of mechanical equipment and numerical control system which is used to process complex shape workpieces. Machining center equipped with a magazine, with automatic tool change function, the workpiece is a clamping after the multi-processing of CNC machine tools. Machining Center is a high degree of integration of mechanical and electrical products, workpiece clamping, the NC system can control the machine according to different processes automatically select, replace the tool, automatic tool, automatically change the spindle speed, feed, etc., continuous drilling, boring, Milling, hinge, tapping and other processes, thus greatly reducing the workpiece clamping time, measurement and machine tool adjustment and other auxiliary process time, the shape of the complex processing, high precision, frequent replacement of varieties of parts with good economic results .

CNC machine tools to achieve the medium and small batch processing automation, improved working conditions. In addition, it also has a high productivity, processing accuracy and stability, product cost and a series of advantages. In order to further develop these advantages, CNC machine tools to the “process concentrated”, that is, a CNC machine tool in a clamping parts to complete the multi-process CNC machine tools (ie machining center) development.

Drilling, boring, milling, car and other single-function CNC machine tools can only be completed drilling, boring, milling, car and other operations, and in the machinery manufacturing industry, most parts are required multi-processing. In the single-function CNC machine tools throughout the processing, the real time for cutting only about 30%, the rest spent most of the time in the installation, adjust the tool, handling, loading and unloading parts and inspection accuracy and other auxiliary work. In the case of parts need to process a variety of processes, single-function CNC machine tool processing efficiency is still not high. Machining centers generally have automatic tool exchange function, parts can be installed after a complete drilling, boring, milling, countersink, tapping and other processing processes.

2. Use

(1) periodic repetitive production of the workpiece. Some of the market demand for products with cyclical and seasonal, if the use of specialized production line is more harm than good, with ordinary equipment processing efficiency is too low, and the quality of instability, the number is difficult to guarantee. The use of CNC machining centers, the first (batch) trial cut, the program and related production information can be retained. The next product reproduction, as long as very little preparation time can begin production. CNC machining center work hours, including preparation time and processing time, CNC machining center to a very long single work hours allocated to each workpiece on an average, so that the actual production of each work to reduce the production cycle is greatly reduced.

(2) high-precision workpiece. Some workpieces require little, but are key components, requiring high precision and short construction period, the traditional process requires more than one machine to coordinate the work of its long cycle, low efficiency, in the long process flow, easily affected by human waste, and thus Resulting in significant economic losses. The use of CNC machining center for processing, production entirely by the program automatically. To avoid the long process flow, reduce the hardware investment and human interference, with high production efficiency and quality and stability characteristics.

(3) mass production of the workpiece. CNC machining center production flexibility not only reflected in the special requirements of the rapid response, and can quickly achieve mass production, in order to improve market competitiveness. CNC machining centers are suitable for small and medium batch production, especially small batch production, in the application of CNC machining centers. Try to make the batch is greater than the economic batch, in order to achieve good economic results. With the continuous development of CNC machining centers, the economic volume is getting smaller and smaller, for some complex parts, 5-10 pieces can be produced, or even single-piece production can also be considered with CNC machining centers.

(4) multi-station and process can be concentrated in the workpiece.

(5) complex shape of the workpiece. Four axes linkage, five axes linkage CNC machining center application as well as the CAD / CAM technology mature, the development, causes the processing work piece the complexity greatly to enhance. The use of DNC to make the same program to meet the processing needs of a variety of processing, so that automatic processing of complex parts become easy.

(6) difficult to measure the workpiece.

3. History of development

Machining centers were originally developed from CNC milling machines. The first machining center in 1958 by the United States Carney – Terrek first successfully developed. It is based on CNC horizontal boring and milling machine to increase the automatic tool changer, so as to achieve a workpiece clamping can be carried out after milling, drilling, boring, reaming and tapping and other processes of centralized processing.
Since the 1970s, the machining center has developed rapidly, there have been interchangeable spindle box machining center, which is equipped with a number of automatic replacement tool with a multi-axis spindle box, the workpiece at the same time porous processing.

4. Classification / machining center

1, according to the classification process
(1) boring and milling
(2) car milling

2, according to the number of control shaft classification
(1) three-axis machining center
(2) four-axis machining center
(3) five-axis machining center.

3, according to the relative position of spindle and table classification
(1) Horizontal Machining Center: refers to the spindle axis and parallel to the table set up processing center, mainly for processing box parts.
Horizontal machining centers generally have indexing turntable or CNC turntable, the workpiece can be processed on all sides; can also be used for multiple coordinates of the joint movement in order to process complex spatial surfaces.

(2) Vertical Machining Center: refers to the spindle axis and the table set up vertical machining center, mainly for processing plate type, disk type, mold and small shell type of complex parts. Vertical machining centers generally do not take turntable, only for the top surface processing.

Vertical machining center_centro mecanizado vertical_FagorAutomation

In addition, there are vertical and horizontal with two spindle machining center, and the spindle can be adjusted into horizontal or vertical axis of the vertical and horizontal adjustable processing center, they can work on the five surface processing.

(3) Universal machining center (also known as multi-axis linkage machining center): refers to the axis through the processing axis and table rotation axis angle can control the linkage changes to complete the complex surface machining surface machining center. It is suitable for machining impeller rotor, mold, cutting tool and other parts with complex surface.
Centralized machining of multiple processes extends to other types of CNC machine tools, such as turning centers. It is equipped with several automatic tool changing devices on CNC lathes. It can control more than three coordinates. In addition to turning, the spindle can be stopped or indexed , And by the rotation of the tool milling, drilling, reaming and tapping processes, suitable for processing complex parts of the rotating body.

5. Composition / machining center

Machining Center is divided into two parts: CNC machine tools and automatic tool exchange.

1, automatic tool exchange device should be able to meet the following requirements:

① tool change time is short;
② high precision tool positioning repeat;
③ Knife knowledge, reliable knife selection, tool change action is simple;
④ reasonable tool storage capacity, small footprint, and with the host to make the appearance of the machine complete;
⑤ tool handling, adjustment, easy maintenance.

2, automatic tool exchange system from the knife library, tool exchange devices, tool transmission device, tool coding device, knowledge, such as the five parts of the knife.

Magazine
Stores warehouses for all types of tools required for machining. It is an important part of the automatic tool exchange system. It has the function of accepting the tool from the tool conveying device and giving the tool to the tool conveying device. Its capacity, layout and specific structure of the entire processing center of the overall layout and performance have a great impact, according to its structure, the shape can be divided into the following six: ① disc magazine, is divided into axial (tool The centerline is parallel to the centerline of the disc), radial (the center line of the tool is perpendicular to the center line of the disc), and the multi-disc type (several layers of disc magazines are arranged on one rotation axis). ② turret-type knife library, and sub-tilt-and horizontal. ③ drum wheel magazine. ④ chain tool library. ⑤ lattice-style knife library. ⑥ linear tool magazine.

Tool exchange device
Its function is to exchange the cutting tool on the spindle of the machine tool with the tool on the magazine or the cutting tool transmission device, the action cycle is: draw the knife – new and old tool exchange – install the knife. The devices are divided into two groups by means of an exchange.
① from the tool magazine and the relative movement of the machine tool spindle to achieve tool change In such devices, the magazine is generally lattice-type, mounted on the table. Tool change, the first table and the relative movement of the spindle, the old knife used back to the magazine, and then make the relative movement of the table and the spindle once, remove the knife from the new knife. This tool change mode of the tool for a long time, another knife set in the table, reducing the effective use of the table area.
② the use of mechanical hand tool changer tool exchange device, in particular the exchange of two-arm manipulator tool changer with a short time, flexible and reliable action, the most widely used. Arms manipulator in the most common structures are: Hook; hold hands; telescopic hand; fork hand. The basic action of a double-arm manipulator to perform a tool change cycle is: grasping the knife (the arm is rotated or extended while grasping the tool in the spindle and the magazine); pulling the knife (the spindle is released and the robot synchronizes the spindle and the magazine (While the new knife into the spindle, the old knife into the magazine, and then the spindle clamping tool); retracted (the arm retracted to the back of the knife); knife Home position).

Transport knife device
When the tool storage capacity is large, the arrangement is far away from the machine, you need to arrange two robots to complete the exchange of old and new knife action, a knife near the library, known as the post-manipulator, complete the new knife, insert the old knife action ; A close to the spindle, known as the former robot to complete the old pull knife, insert a new knife action. Between the front and rear manipulators are equipped with a knife device. Which on the one hand the former robot from the spindle to pull out the old knife back to the library next to the robot to pull out the old knife and inserted back to the magazine; the other hand will pull out of the robot after the new library The knife is transported to the spindle so that the front robot can pull the new tool out and insert it into the spindle. The function of transporting the knife is to transport the old and new tools back and forth between the front and rear manipulators.

Tool coding device to process the necessary tool automatically selected from the magazine out as automatic selection knife, there are order selection and coding options in two ways.

Sequential selection method All the tools required for machining a part on the machining center are inserted into the magazine sequentially in sequence. Processing in accordance with the processing order one by one access. Using this tool does not need to know knives, knife library structure and its drive is very simple, each time the tool changer to control the turntable once. The disadvantage is that the tool in the magazine can not be reused.

Encoding selection mode
All the tools (or tool holders) required to machine a part are pre-coded and stored in the magazine. According to the process of processing to find the necessary tools. Since each tool has its own code, its position and storage sequence in the magazine can be independent of the machining sequence. Each tool can be reused multiple times. Tool coding in a variety of ways, there are three commonly used. ① tool code: the end of each tool in the coding ring with their own numbers. The tool is selected according to the tool number command issued by the punch tape. As each tool has its own code to determine, no matter which tool will be placed in the tool magazine will not affect the correct knife. The use of this encoding can simplify the tool change action and control lines, shorten the tool change time. This code has now been widely used. ② Tool Block Encoding: Encoders are coded on each tool holder of the magazine. The advantage of this coding method is that the handle will not increase the length due to the end of the coding ring; the disadvantage is that the tool must be seated, tool change time is long. ③ Encoding key: In advance, each tool is tied with a coding key indicating the tool code. When the tool is inserted into the tool holder of the magazine, the key is also inserted into the key hole of the tool holder, The code on the key to the knife in mind, as the code of the knife block. This code has the advantage of replacing the processing of parts only need to remove the key from the knife seat, the knife on the code itself will disappear, flexibility, for tool management and programming are very beneficial and less prone to human error. The disadvantage is that the tool must be seated.

Knife knowledge device
It is the function of the tool to read the code from the encoding device. Knife knowledge commonly used contact and non-contact two. ① contact knifed knife device: This approach is relatively simple and reliable, it corresponds to the coding device and the convex part of the groove is equipped with a row of brushes, knife selection, the knife rotation, the tool coding device in turn through the brush, The convex part and the brush contact, read the tool code. ② non-contact knowledge Knife device: it is arranged by a group of non-contact travel switch composition. When the magazine rotates, the protrusions (made of ferromagnetic material) of the tool encoders close to the knifing tool, the tool code is read. The knifed knives do not impact, no noise, no wear, long life, can be used for high-speed election knife, but the work is not stable enough, debugging more difficult.

6. Advantages

After the workpiece in the machining center after a clamping, the digital control system can control the machine according to different processes, automatic selection and replacement of the tool, automatically change the machine tool spindle speed, feed and tool relative to the workpiece trajectory and other auxiliary functions, in turn The workpiece surface on several processes of processing. And a variety of tool change or knife function, so that production efficiency greatly improved.

The machining center can reduce the workpiece clamping, measuring and machine adjustment time, and make the cutting time of the machine reach about 80% of the machine start time (15 ~ 20% of the general machine tool). At the same time, But also reduce the process between the workpiece turnover, handling and storage time, shortening the production cycle, with significant economic results. The machining center is suitable for small and medium-volume production with complex part shapes, high precision requirements and frequent product changes.

7. Maintain

The machining center regularly checks the project
1, the spindle at the maximum speed of operation under the state of bearing vibration meter
2, equipment level detection level
3, X / Y / X axis perpendicularity detection square box / square
4, X / Y / Z-axis repeat positioning accuracy detection laser interferometer (depending on the equipment brand can automatically compensate)
5, X / Y / Z axis cumulative error detection laser interferometer (depending on the device brand can automatically compensate)
6, spindle 300mm radial runout detection
7, the vertical axis and the work surface detection
8, X / Y / Z-axis ball screw bearings state detection,
9, X / Y / Z axis screw status detection

Periodic maintenance of the machining center
Mechanical parts
1, check the lubrication system, pressure gauge state, cleaning the lubrication system filter, replace the oil, dredge the oil,
2, check the gas system, clean the air filter to eliminate the pressure gas leakage.
3, check the liquid system, clean the filter, clean the tank, replace or filter the oil. If possible, replace the seal.
4, fastening the transmission parts, replacement of bad parts.
5, grease lubrication parts, as required, filling grease
6, cleaning, cleaning the transmission surface,
7, Check the magazine, manipulator status, analysis of wear state of the robot, the replacement of the proposed recommendations to customers.
8, repair repair external components damaged pieces.
9, check the protective cover status. Accurate feedback to the customer information.
Electrical part
10, clean the electrical components within the control cabinet, check, tighten the fastening terminal state.
11, cleaning, cleaning CNC system control module, circuit boards, cleaning fans, air filters, clean the cooling device,
12, clean the servo motor fan blades.
13, cleaning operation panel internal components, circuit boards, fans. Check the fastening condition of the connector.

8. Maintenance methods

Do a good job of machine maintenance to make the machine processing accuracy to maintain the best condition, to extend the useful life of the machine. Note: After starting the machine, the maintenance of the machine is prohibited. During maintenance, the circuit breaker should be disconnected.

Machining precision maintenance:
1, boot, you must warm up about 10 minutes, and then processing. Long-term use of the machine should be extended preheat time. 2, check the oil is smooth 3, shut down before the table, saddle in the machine central location (moving three-axis travel to the axis of the middle position). 4, the machine to keep dry and clean.

Maintenance inspection:
(1) daily maintenance
1, check the oil level, to ensure that machine lubrication. T68 # guide rail oil is recommended. 2, check the coolant tank coolant is enough, not enough time to add. 3, check the pneumatic triple oil level, about the height of the entire tubing 2/3 can. Pneumatic three-piece filter tank water every day by the drainage switch discharge. 4, check the air pressure, relax the adjustment knob, according to the right-handed booster, L-pressure to adjust the pressure, the general set to 5 ~ 7KG / CM2. Pressure switch is usually set to 5 KG / CM2, less than 5KG / CM2 when the alarm, the system “LOW AIR PRESSURE” alarm, the pressure increases, the alarm message disappears. 5, check the spindle hole blowing air is normal, with a clean cotton cloth to wipe the spindle hole, and sprayed with light oil. 6, cleaning knife library arm and knives, especially the knife claws. 7, clean the exposed limit switches and touch block. 8, to remove the table, machine tools, three-axis telescopic shield on the cutting and oil. 9, check all the lights, abnormal warning lights are normal. 10, check the hydraulic unit pipe is a leakage phenomenon. 11, the machine after the completion of daily cleaning and cleaning work. 12, to maintain the environment around the machine clean and tidy.

(2) weekly maintenance
1, cleaning the heat exchanger air filter, cooling pump, oil pump filter. 2, check the tool pull bolt is loose, the knife is clean. 3, check whether the three-axis mechanical origin offset. 4, check the magazine tool changer arm movements or knife library cutter rotation is smooth. 5, if the oil cooler check oil cooler oil, such as below the scale line, please add oil cold oil. Recommend the use of 10 # spindle oil. 6, check the oil cooler set temperature, the proposed set between 26-28 degrees.

(3) monthly maintenance
1, the detection of X, Y, Z three-axis orbit lubrication, orbital surface must ensure good lubrication. 2, check, clean limit switch and touch block. 3, check the knife cylinder oil cup oil is sufficient, lack of timely addition. 4, check the signs on the machine and the warning nameplate is clear, there.

(4) six months of maintenance
1, open the three-axis chip guard, cleaning the three-axis tubing connector, ball screw, three-axis limit switch, and detect whether normal. Check the hard shaft scraping brush the effect of the shaft is good. 2, check the servo motor and the head of each axis is normal operation, with or without abnormal sound. 3, the replacement of hydraulic unit oil, oil reduction gear library. 4, test the shaft clearance, if necessary, adjust the amount of compensation. 5, clean the dust inside the electrical box (to ensure that the machine is turned off). 6, a comprehensive inspection of the contacts, connectors, sockets, switches are normal. 4, check and adjust the mechanical level.

(5) years of maintenance
1, check all keys are sensitive and normal. 2, cleaning cutting water tank, replace the cutting fluid. 3, check the vertical axis accuracy, decide whether to adjust.

Routine maintenance and repair
CAUTION: Maintenance and repair of equipment should be performed by a qualified engineer.
1, grounding protection system should have good continuity, to ensure personal safety. 2, on the circuit breaker, contactors, single-phase or three-phase arc extinguishers and other vitality parts for regular inspection. Such as wiring is loose, the noise is too large, find out the reasons and eliminate hidden dangers. 3, to ensure that the normal operation of the cooling fan cabinet, otherwise it may lead to damage to vitality. 4, the fuse blows, air switch frequent tripping, should promptly find out the reasons and exclude.

(6) Replace the servo drive battery
Absolute system data is maintained by the servo drive battery. When the battery voltage is too low (warning 9F), the drive battery needs to be replaced. Please order the same type battery unit as soon as possible and keep the power supply connected. Turn on the power of the drive unit 30 minutes before replacing the battery, and replace the battery in less than one hour.
Battery replacement procedure
1. Make sure that the input power is cut off and the power supply of the replaced drive unit is OFF. 2. Pull out the battery connector connected to the battery socket of the drive unit. 3, press the side of the battery with your fingertips, horizontal push the battery and then remove. 4, the new battery plug and drive unit battery socket connected. 5, the battery installed on the drive unit.

9. Safety rules

1, must abide by the processing center safe operating procedure.
2, before the work should be required to wear good protective equipment, good cuffs, not allowed to wear scarves, wearing gloves, tie, Wai aprons, women workers should be rolled in the hat.
3. Check whether the tool compensation, machine zero and workpiece zero are correct before starting.
4, the relative position of the button should meet the operational requirements. Carefully prepared, enter the NC program.
5, to check the equipment protection, insurance, signal, position, mechanical transmission part, electrical, hydraulic, digital and other systems operating conditions, in all normal circumstances before cutting.
6, the machine before the test run, should check the lubrication, machinery, electrical, hydraulic, digital and other systems operating conditions, in all normal circumstances can be cutting.
7, the machine according to the program into the processing operation, the operator is not allowed to contact with the movement of the workpiece, cutting tools and transmission parts, rotating parts across the machine to prohibit the transfer or take tools and other items.
8, adjust the machine, clamping the workpiece and tool and wipe the machine, you must stop for.
9, tools or other items are not allowed on the electrical, operating cabinets and protective cover.
10, are not allowed to directly remove iron scraps by hand, should use special tools to clean.
11, abnormal conditions and alarm signals should be immediately stopped, the relevant personnel to check.
12, are not allowed to leave the job when the machine is running, for reasons to leave, the workbench on the middle position, Arbor returned, must stop, and cut off the host power.

10.Other references

cnc-milling-machine
cnc router
cnc-lathe-machine-buyers
3d-printer
cnccomputer-numerical-control
cnc-grinding-machine
cnc-drilling-machine

11.List of CNC Machining Center manufacturers

ManufacturerHQProducts Built
Toyoda Machinery USA CorpUShorizontal machining centers, vertical machining centers.
Okuma America CorporationUSCNC turning machines, machining centers, portal type machining centers, grinding machines.
NTC America CorporationUSmachining centers, grinding machines, crankshaft milling machines.
Mitsui Seiki (USA) Inc.USmachining centers, jig boring machines.
L.K. Machinery, Inc.USCNC machining centers, die casting machines.
Komo Machine, Inc.USCNC axis machining centers, entire line of high quality precision computer numerically controlled (CNC) routers and machining centers.
Hurco Companies, Inc.US5 axis machining centers, turning centers.
Ganesh Machinery, Inc.USCNC screw machines, CNC milling machines, CNC turning center, multitasking machines, multi axis CNC bar machines, CNC turn mill centers, CNC machining centers.
Fryer Machine Systems, Inc.US5 axis machining centers, turning centers.
Eurotech EliteUSmulti axis machining centers, turning centers.
Doosan Infracore Machine ToolsUSturning centers, machining centers, horizontal boring mills, portal type machining centers, Swiss lathe, EDM.
Clausing Industrial, Inc.USturning machines, milling machines, sawing machines, drilling machines, grinding machines, machining centers.
Cellular Concepts Co. (Cell-Con)USCNC horizontal machining centers, also 3-axis CNC machining modules applicable to transfer lines.
APECTaiwan5 axis machining centers.
Akira Seiki Co. Ltd.Taiwanmachining centers, turning centers, tapping centers, BT-40 horizontal machining center, RMV-RT series multi-faces machining center, Performa mass production center.
MTAB Engineers Pvt Ltd.IndiaCNC turning centers, CNC machining centers, mini robots.
EMAGGermanymachining centers, turning machines, grinding machines, tube machining centers.
ALZMETALL WerkzeugmaschinenfabrikGermanydrilling machine, milling machine (5-axis cnc machining center), machining centers.
ALFING KESSLER SONDERMASCHINENGermanymachining centers, transfer lines, con rod machining machines.
Qinchuan Machine Tool & Tool Group Co., Ltd.Chinamachining centers, gear hobbing machines.
Zhejiang RIFA Digital Precision Machinery Co., Ltd.Chinamachining centers, CNC lathe, CNC gantry milling machine, bearing grinding machines.
Ningjiang Machine Tool Group Co., Ltd.Chinamachining centers, flexible manufacturing systems, 5 axis machining center.
Ningxia Zhongwei Dahe Machine Tool Co., Ltd.Chinahoning machines, machining centers, drilling machines.
Ningxia Yinchuan Dahe CNC Machine Co., Ltd.China honing machines, machining centers, CNC drilling & milling machines.
Guangzhou Machine Tool Works Co., Ltd.ChinaCNC lathe, conventional lathe, machining center.
Euma (Jiangsu) CorporationChinamachining center, portal type machining centers.
Tengzhou Mainland Machine Tool Co., Ltd.Chinamachining centers, vertical lathe, portal type milling machines, drilling and milling machines.
Beijing Yichuanchuangye CNC Equipment Co., Ltd.ChinaCNC turning machines, CNC milling machines, machining centers.
Zhejiang Shuangniao Digital Machine Tools Co., Ltd.ChinaCNC lathe, horizontal machining centers, vertical machining centers, double column machining centers.
TOS Kunming Machine Tool Co., LtdChinafloor type boring and milling machine, planer type boring and milling machine, cnc machining centers.
Ningbo SKY Master Precision Machinery Co., Ltd.Chinamachining centers, heavy duty milling machines, high speed machining centers.
Nanjing J&W Manufacturing Co., Ltd.Chinamanual milling machines, machining centers, portal type machining centers, vertical lathe, drilling machine, boring & milling machine.
Jinan First Machine Tool Group Co., Ltd.ChinaCNC turning machines, CNC machining centers, CNC boring & milling machines.
Nanjing CNC Machine Tool Co., Ltd.Chinaturning machines, milling machines, vertical machining centers.
Hangzhou Datian CNC Machine Tool Co.,Ltd.Chinavertical machining centers.
Beijing Machine Tool Research InstituteChinamachining centers.
Shandong Linyi Jinxing Machine Tool Co., Ltd.ChinaCNC milling machines, CNC machining centers.
Dalian Machine Tool Group CorpChinadrilling & milling center, CNC turning machines, machining centers, CNC milling machines.

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