CNC Machine Tools Return troubleshooting

CNC Machine Tools Return troubleshooting

Manual reference point return operation of the machine coordinate system is built on thepremise, most of the first CNC machine is turned on manually operated actions are generally the reference point.Cnc machining  If the reference point back to the failure processing program will not be able to return the position of the reference point will not affect the accuracy of machining accuracy, or even crash.

      Analysis and excluded the issue back to the reference point of failure is necessary.

 1. Back to the main types of reference point of failure   

   A CNC machine operator training center has 20 CNC machine tools, and is purchased in batches, the system more types of students training in the operation, there have been back several times reference point of failure, through the timely analysis was excluded.     

 According to experience,Cnc machining   different systems in different models of CNC machine tools, there back to the reference point of failure, mainly in the following five categories: super-way there and the police; back less than a reference point, the reference point indicator does not light; back to the reference point instability; back to the whole pitch offset reference point; back to the reference point the alarm, and alarm information.

   2. Back to the reference point troubleshooting   

   The process occurs over and the police, divided into two cases. One case is the reference point before the position of the axes from the reference point resulting from too small. Lift overtravel protection, and will move to the travel axis within the scope of the reference point to re-operation, to troubleshooting; other is the "reference point deceleration" block loose or change position due to failure to re-adjust the fixed block to be troubleshooting.

  Back to the reference point due to the amount of the reference point indicator is off. Diagnostic capabilities through the machine in the diagnosis of the page under the corresponding "Location tracking error" (dgn800 ~ 802) to check if the positioning accuracy of the tracking error exceeds the permissible range, you can adjust the servo drive, "offset" potentiometer so that the " Position tracking error "(dgn800802) value close to" 0 ", you can troubleshoot.    

   There reference point for the unstable failure, first check the location and block exposure, and then check the pulse encoder "zero pulse" if there are problems, the last check the gap between the motor and lead screw. If the unstable displacement error is small, usually among the last case, the gap should be eliminated to remove a loose connection.    

   Reference point the whole pitch shift. When the workpiece is always stable  displacement error occurred, and exactly equal to the screw pitch, then the problem lies in the back reference point. Reference points are generally located in the "reference point slow down" after the opening of the first block of a "zero pulse" on. If the block release, the encoder happens in the "zero pulse" in the vicinity, there will be a whole pitch shift. Need to re-adjust the deceleration stop position, preferably slow release position and the block encoder "zero pulse" position, a difference of half a pitch.       

  Back to the reference point for the alarm, and fault alarm. For alarm information, view the machine instructions for the appropriate treatment. Message alert may belong to: encoder "zero pulse" and the system grating bad bad bad shield, the system parameter setting error and other failures. Cnc machining  For the hardware bad need of repair or replacement; for parameter setting error, you need to reset the parameters by backups.

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NC system maintenance

NC system maintenance

  1.Strictly abide by the rules and routine maintenance of the system

 2. Numerical control device to prevent dust from entering

  Floating dust and metal powder easily lead to decreased Cnc machining insulation resistance between    components, which failure or even damage to components.

     3. CNC cabinet cooling time cleaning the ventilation system

     4. Regular monitoring system of mains voltage NC

     Rated grid voltage in the range 85% to 110%.

     5. Periodic replacement of storage batteries

      6. When not in NC long-term maintenance of the system

 Often to the NC system power or to run the warm machine program CNC machine tools.

  7. Spare circuit board to maintain the maintenance of mechanical  Cnc machining  components  Maintenance of mechanical parts

    1. Tool and maintenance of mechanical hand tool change 

① Tool to manually upload tool, to ensure that equipment in place to check the reliability of the locking blade seat;

      ② strictly prohibited overweight, long knives into the knife, to prevent the robot tool change out a knife or cutting tool and workpiece, fixtures and other collision;

     ③ The Tool Selection should be noted that the order placed in the magazine on the tool order is correct. Other options should also take note of the way Cutter number for the tool is consistent with the required tools to prevent the wrong tool for the accident cause;    

  ④ keeping a clean tool holder and tool pocket;

 ⑤ always check the magazine's back to zero position is correct, check the spindle back to the tool change position is in place, and adjusting, or can not complete the tool change operation;    

  ⑥ boot, should be made and the mechanical hand tool storage space to run, check each part is working properly, especially the limit switch and solenoid valve can operate normally.     

 2. Maintenance of ball screw      

① periodic inspection, adjustment screw nut axial clearance, to ensure the accuracy and axial stiffness of the reverse drive;    

  ② periodically check the screw connections support and the bed is loose and the support bearings for damage. If these problems to tighten the loose parts in a timely manner, the replacement of support bearings;    

  ③ The grease of the ball screw, lead screw washed once every six months old on the oil, replace oil. The ball screw with lubricating oil, grease once a day before work machine;

      ④ hard to avoid dust or chips into the screw shields, and the work process crashing shields, protective devices should be replaced whenever damaged.

 3. Maintenance of the main drive chain

      ① adjusted periodically with the tightness of the spindle drive;

      ② to prevent all kinds of impurities into the fuel tank. Replaced once a year oil;

     ③ Connect the handle to keep the spindle area clean. The need for timely adjustment of the hydraulic cylinder and piston displacement;

     ④ To adjust the weight in time.   

  4. Hydraulic system maintenance      

    ① or replacement of oil filter on a regular basis; 

    ② control the temperature of the hydraulic system oil; 

    ③ to prevent leakage of hydraulic system;    

 ④ tank and pipe cleaning regularly checked;  

  ⑤ routine point inspection system.    

 5.  Cnc machining  Pneumatic system maintenance   

  ① remove air impurities and moisture;    

 ② Check the oil mist system, the fuel supply;  

   ③ to maintain the tightness of the system;    

 ④ attention to regulating the working pressure;

   ⑤ cleaning or replacement of pneumatic components, filters;

Classification by control

Classification by control

  Open-loop control; that position feedback devices without control.

  Semi-closed loop control; Cnc machining refers to the open-loop control with servo motor shaft angular displacement detecting device, by detecting the servo motor to detect indirectly the corner of the displacement of moving parts back to the NC device comparator compares the input command, with the difference value controls the moving parts.    

  Closed-loop control; is in the final of the moving parts of machine corresponding direct linear or rotary position detection device, will be directly measured value of

displacement or angular displacement feedback to the CNC device with comparator

compares the input command shift, Cnc machining with the difference value control moving parts, so

that moving parts in strict accordance with the actual needs of the displacement。

 movement.

  ● control of machines by the number of performance categories

    Economical CNC machine tools;

    Mid-range of CNC machine tools;

    High-end CNC machine tools;

     ● CNC equipment used by way of fractional composition of

    Hard-line numerical control system;

    Soft-line numerical control system;

Maintenance of CNC machine tools

      Overview of CNC machine tool maintenance

 Components and parts to extend wear life cycle, prevention of failure and improve the CNC machine tools, the average time between failures and service life.  CNC machine tools in use should be noted that the problem   

 1. The use of CNC machine tools environment     

 CNC machine tools the best place for them away from the constant temperature and vibration environment of the larger equipment (such as the punch) and electromagnetic interference equipment.    

 2. Power Requirements      

3. Practice for CNC machine tools should be    

  Regular maintenance, maintenance, Cnc machining failure of attention to such records to protect the scene.      

4. Not long-term storage of CNC machine tools     

 5. Attention to training and equipment operators, maintenance personnel and programming staff.

Characteristics of CNC machine tools

Characteristics of CNC machine tools

 CNC machine operation and monitoring of all completed in the numerical control unit,Cnc machining  which is the brains of CNC machine tools. Compared with the general machine tools,

CNC machine tools has the following characteristics:

 ● high precision, stable processing quality;

   ● can be multi-axis linkage, can process complex shape parts;

  

● processing part changes, generally only need to change the NC program, saving the production time to prepare;

   ● high precision

machine tool itself, rigidity, can choose the amount of benefit processing, production rate (usually as an ordinary machine 3 to 5 times);

 ● high degree of automation tools, can reduce labor intensity;

  ● the quality of the operators require a higher tech

nical requirements on higher maintenance staff

 CNC machine tools generally consists of the following components: 

● host, he is the subject of CNC machine tools, including machine tools, column, spindle, feed mechanism and other mechanical parts. He is used to complete a variety of machining mechanical parts.

● CNC equipment, CNC machine tools is the core, including the hardware (printed circuit boards, CRT monitors,Cnc machining  key boxes, paper tape reader, etc.) and the corresponding

software for digital input part program, and complete the input information storage, data transformation, interpolation operations and achieve a variety of control functions.

● drive, he was the implementing agencies CNC drive components, including the spindle

drive unit, feed unit, spindle motor and feed motor. He was under the control of the NC

device electrical or electro-hydraulic servo system to achieve through the spindle and feed drive. When several feed linkage, you can complete the position, line, plane curves and space curves processing.

● assist device, the index control machine tools necessary supporting components to

ensure the operation of CNC machine tools, such as cooling, chip removal, lubrication, lighting, monitoring. It consists of hydraulic and pneumatic devices, chip equipment, pallet, NC rotary table and CNC dividing head, including tools and monitoring detection devices.

  ● Programming and other ancillary equipment, can be used to machine the part outside the programming and storage.       

 Since 1952, Massachusetts Institute of Technology developed the world since the first CNC machine tools, CNC machine tools in manufacturing industry, especially in the automotive, aerospace, Cnc machining and military industries has been widely used, digital technology both in hardware and software have rapid development.

  

  

Grinding

Grinding 

  Cnc machining is one of the most widely used methods of finishing parts to extremely close tolerances and low surface roughness.

 Currently, there are grinders for almost for almost every type of grinding operation. Particular design features of a part dictate to a large degree the type of grinding machine required. Where processing costs are excessive, parts redesigned to utilize a less expensive, higher output grinding method may be well worthwhile. For example, wherever possible the production economy of center less grinding should be taken advantage of by proper design consideration.

   Although grinding  Cnc machining  is usually considered a finishing operation, it is often employed as a complete machining process on work which can be ground down from rough condition without being turned or otherwise machined. Thus many types of forgings and other parts are finished completely with the grinding wheel at appreciable savings of time and expense.  Classes of grinding machines include the following: cylindrical grinders, center less grinders, internal grinders, surface grinders, and tool and cutter grinders。

 The cylindrical and center less grinders are for straight cylindrical or taper work; thus splices, shafts, and similar parts are ground on cylindrical machines either of the common-center type or the center less machine.

  Thread grinders are used for grinding precision threads for thread gages, and threads on precision parts where the concentricity between the diameter of the shaft and the pitch diameter of the thread must be held to close tolerances.  The internal grinders are used for grinding of precision holes, cylinder bores, and similar operations where bores of all kinds are to be finished.

  The surface grinders are for finishing all kinds of flat work, or work with plain surfaces which may be operated upon either by the edge of a wheel or by the face of a grinding wheel.Cnc machining   These machines may have reciprocating or rotating tables.

  

Automatic Tracer Lathes and Milling

Automatic Tracer Lathes and Milling

 Cnc machining Since surface roughness depends greatly upon material turned, tooling, and fees and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances. 

    Is some case, tolerances of ±0.05mm are held in continuous production using but one cut. Cnc machining   Groove width can be held to ±0.125mm on some parts. Bores and single-point finishes can be held to ±0.0125mm. On high-production runs where maximum output is desirable, a minimum tolerance of ±0.125mm is economical on both diameter and length of turn.

  Milling  

  With the exceptions of turning and drilling, milling is undoubtedly the most widely used method of removing metal. Well suited and readily adapted to the economical production of any quantity of parts, the almost unlimited versatility of the milling process merits the attention and consideration of designers seriously concerned with the manufacture of their product.  

 As in any other process, parts that have to be milled should be designed with economical tolerances that can be achieved in production milling. Cnc machining   If the part is designed with tolerances finer than necessary, additional operations will have to be added to achieve these tolerances——and this will increase the cost of the part.

  

Machining

Machining

  Turning The engine lathe, Cnc machining one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered. 

 The engine lathe has been replaced in today's production shops by a wide variety of automatic lathes such as automatic of single-point tooling for maximum metal removal, and the use of form tools for finish and accuracy, are now at the designer's fingertips with production speeds on a par with the fastest processing equipment on the scene today.

  Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilled operator. Cnc machining In redesigning an experimental part for production, economical tolerances should be used. 

 Turret Lathes 

   Production machining equipment must be evaluated now, more than ever before, in terms of ability to repeat accurately and rapidly. Applying this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating.

  In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turret lathe, the designer should strive for a minimum of operations.

   Automatic Screw Machines 

  Generally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle automatics and automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts,Cnc machining  the automatic screw machine has long since exceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic to set up on the turret lathe than on the automatic screw machine. Quantities less than 1000 parts may be more economical to set up on the turret lathe than on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities