Reasons for unstable quality of CNC machined parts
CNC lathe processing is used in many parts and appearances.Because of its high precision and high production efficiency,we often encounter some problems in the machining of CNC lathes,and the quality of the machined parts is unstable.Next,the small side will give you an analysis of the reasons for the unstable quality of the processed parts.
1,the workpiece scale is accurate,the surface finish is poor
Possible reasons:the tool tip is damaged,not sharp;the machine tool resonates,the placement is not stable;the machine tool has flaws;the processing technology is not good.
Solution:If the tool is not sharp after being worn or damaged,re-grind the knife or pick a better tool to re-align the tool;the machine will resonate or be placed unevenly,adjust the level,lay the bottom,and fix it smoothly;The guide rails are worn fiercely,and the lead screw is worn or loose.The machine should pay attention to maintenance.After work,the wire should be cleaned and the lubricant should be added in time to reduce the conflict.Select the coolant for the workpiece processing,and reach the processing requirements of other processes.In the case,try to use a higher spindle speed.
2,the workpiece has a taper size
Possible reasons:the level of the machine tool is not adjusted well,one high and one low,the placement is not stable;when turning the long axis,the dedication information is relatively hard,the tool is deeper,the shape
Let the knife phenomenon;the tailstock thimble is not concentric with the spindle.
Solution:Use the level to adjust the level of the machine,lay a thick foundation,fix the machine to improve its resistance;choose a reasonable process and the appropriate cutting feed to prevent the tool from being forced to make the knife;adjust the tailstock.
3.The driver phase lamp is normal,and the processed workpiece scale is large and small.
Possible reasons:the machine tool carriage runs at high speed for a long time,which causes the screw and bearing to wear.The repeated positioning accuracy of the tool holder occurs in the long-term operation.The carriage can accurately return to the machining starting point every time,but the machining workpiece scale is still changed..This phenomenon is generally caused by the main shaft,and the high-speed rolling of the main shaft causes the bearing to wear severely,resulting in a change in the processing scale.Metal processing WeChat,the content is good,it is worthy of attention.
Solution:Use the dial gauge to lean against the bottom of the tool holder,and then fix a fixed cycle program through the system,check the repeat positioning accuracy of the carriage,adjust the screw gap,replace the bearing;use the dial indicator to check the repeat positioning accuracy of the tool holder.Adjust the machine or replace the tool holder;use a dial indicator to check whether the workpiece is accurately returned to the starting point of the program.If possible,repair the spindle and replace the bearing.
4,the workpiece scale is different from the actual scale by a few millimeters,or a certain axial change
Possible reasons:the speed of rapid positioning is too fast,the drive and the motor are not overwhelming;after the long-term collision loss,the mechanical lead screw and the bearing are too tightly stuck;the tool holder is too loose after the tool change,and the lock is not tight;The program is faulty,the head and tail are not taken care of or the tool is not revoked;the electronic gear ratio or step angle of the system is set wrong.
Solution:The fast positioning speed is too fast,the GO speed is adjusted properly,the cutting acceleration and deceleration and the time make the drive and the motor work normally at the extra running frequency;the pallet and the screw crane bearing are too tight after the machine wear is presented.If the card is stuck,it is necessary to re-adjust the correction;if the tool holder is too loose after the tool change,check whether the tool holder reversal time is satisfactory,check whether the worm gear inside the tool holder is worn,whether the gap is too large,whether the device is too loose,etc.;If the program is formed,it is necessary to correct the program,improve according to the requirements of the workpiece drawings,select a reasonable processing technology,and write the correct program according to the instructions of the manual;if the scale error is too large,check whether the system parameters are set properly,especially the electronics.Whether the parameters such as the gear and the step angle are damaged,this phenomenon can be measured by dialing the dial indicator.
5,the processing arc is not ambition,the scale is not in place
Possible causes:overlapping of vibration frequency leads to resonance;processing technology;parameter setting is unreasonable,feed rate is too large,and arc machining is out of step;looseness caused by screw gap or loose step caused by screw over tightening;abrasion.
Solution:Find out the parts that have resonance,change their frequency,prevent resonance;consider the processing technology of the workpiece data,and make the program reasonably;for the stepping motor,the processing rate F can't be set too large;whether the machine is strong,stable,drag Whether the board is too tight after wear,the gap is increased or the tool holder is loose,etc.;replace the timing belt.Metal processing WeChat,the content is good,it is worthy of attention.
6,in mass production,accidentally presented the workpiece is out of tolerance
Possible reasons:It is necessary to carefully check the fixtures,and take into account the operator's operation method and the reliability of the clamping.Because of the scale changes caused by the clamping,it is necessary to improve the tooling so that the workers can prevent human error from misjudging as much as possible;The system may be subject to fluctuations or disturbances of the external power supply,and then actively generate an disturbance pulse,which is transmitted to the drive to cause the drive to accept the remaining pulse-driven motor to take away or less.
Solution:Understand the rules,try to use some anti-interference methods,such as:strong electric cable disturbed strong electric cable and weak electric signal signal line barrier,participate in anti-interference absorption capacitor and shielded line barrier,in addition,view the ground Whether the connection is strong,the grounding contact is recently,and all anti-interference measures are adopted to prevent the system from being disturbed.
7.The machining of a certain process of the workpiece has been changed,and the scale of other processes is accurate.
Possible cause:Whether the parameters of the program block program are reasonable,whether it is in the reserved track,whether the programming pattern meets the requirements of the manual
Solution:When the thread block is chaotic,the pitch is wrong,it immediately associates with the peripheral equipment(encoder)of the thread and the objective factors of the function.
8,each process of the workpiece has a phenomenon of increasing or decreasing
Possible reasons:the program is written incorrectly;the system parameter setting is unreasonable;the equipment setting is not proper;the mechanical transmission parts have regular periodic changes.
Solution:Check whether the instructions used by the program are fulfilled according to the requirements specified in the manual.It can be judged by dialing the dial indicator.The dial indicator is positioned at the starting point of the program to let the board return to the starting position after the program is completed,and then repeat the performance.Even if the results of the investigation are investigated,the rules are checked;whether the system parameters are set reasonably or are considered to be changed;whether the relevant machine tool equipment meets the requirements of the single-counting calculation on the coupling parameters of the connection accounting,whether the pulse equivalent is accurate;whether the transmission part of the machine tool is damaged or not,the gear Whether the coupling is uniform,check whether there is periodicity,regularity,and if so,check the key parts and give them a sweep.
9.The scale changes caused by the system are unstable.
Possible causes:The system parameter setting is unreasonable;the operating voltage is unstable;the system is disturbed by the external,resulting in the system out of step;the capacitor is added,but the impedance between the system and the driver does not match,causing the useful signal to be lost;the signal between the system and the driver Transmission is not normal;system damage or internal problems.
Solution:speed,speed up the time is too large,spindle speed,cutting speed is reasonable,whether the operator's parameter correction leads to system function changes;install voltage regulator equipment;ground wire and conclude that it has been firmly connected,in the driver pulse output contact Add anti-interference absorption capacitor;select the appropriate capacitor model;check whether the signal connection between the system and the driver is shielded,whether the connection is reliable,check whether the system pulse signal is lost or added;send the factory to repair or replace the motherboard.
The above is the reason analysis and solution for the unstable quality of CNC lathe processing parts.In order to ensure the quality of CNC lathe processing parts,it is necessary to solve the problem in time when the lathe has problems.In the weekdays,we also pay attention to the maintenance of CNC lathe processing.To minimize the occurrence of these problems.