The safe hidden trouble that numerical control machine tool can not be ignored
From:Taian Haishu Machinery Co.,Ltd. Updatetime:2015-12-7 12:45:45 Views：
1, the background editing functionsIn FANUC series oi Mate TB in the system, the manufacturer in order to make the operator processing convenience, set the background editing functions, namely in the automatic processing process, but in the case of not terminate processing, the program edit mode for the current program edit modifications or other programs for the background;Also can choose to "the handwheel way" will control mode, by turning the handwheel making knives, so as to change the position of the processing centers.Background editing features convenient operator in the process of machining of parts manufactured by modified, simplify the operation process.But this kind of simplified, has brought a serious hidden trouble for safety operation, in the teaching practice, students frequently occur wrong operation.When the control mode selection to "automatic cycle", if the machine chuck clamping or not tail stock no ejection (that is, the machine is not ready), press the "cycle start" button, the machine is not operating.At this time will choose to "manual" control mode, make the machine chuck clamping, tail frame ejection (i.e., machine tool ready), are just the selected "cycle start" command is valid, program automatically.If the operator is loading, the hand also did not leave the artifacts, again there is a main shaft in the program startup instruction, the operator easy to hurt the hand, even serious safety accident may occur.The solution is as follows.Ladder diagram 1) manufacturers to adjust system, change the launch conditions of the "cycle start" button, which need to be in "chuck clamping", "stern frame top tight" cases, all prepared in the way of "automatic cycle" or "MDI" down "cycle start" button to work, the lack of any of them are invalid."Or" relationship into a chuck clamping - end cap is tight - automatic way - cycle start "and" relationship.But this change will make editing "the background" not work, for the operator need to processing while change program will be difficult, but in the pay more attention to the safety of mechanical engineering practice teaching, this change is very necessary.2) cancel the existing order.In the "automatic mode" after pressing "cycle start" button is invalid, then press the "reset" button to cancel the existing order, even if "chuck clamping", "stern frame top tight", "automatic mode" program will not automatically perform, need operation "cycle start" button again.This method will be dangerous to eliminate in the bud, is worth popularizing in the application.2, machine tool power problem
NC machine tools with NC system (digital control system), NC machine shutdown can effectively save the data requirement, therefore NC system has its own power-fail protection standby power supply.When NC power supply power is not enough, need to replace the battery in time, to ensure that the data is not lost.
However because of NC system has memory function, if the operators are working in the machine tool for processing, others will be closed the main supply of machine tool, the machine plate uncontrolled could move on, machine tools, crashed accident.At the same time, because of NC power supply instantaneous electric current too big, easy to burn out machines.NC machine tools, therefore, switch machine should have the order: boot first open external total power, to open the machine total power, finally open NC power supply.Shutdown to close the NC power supply first, then turning machine total power, in determining the closed in the absence of any other machine tool use external power source, is the opposite of boot sequence.
The determination of 3, Siemens system operation option
Siemens system for the control panel procedures require options from time to time determine.As shown in figure 1, when making the knife operation, when finish the X axis and Z axis to knife, shown on the display for the new data.But if you don't press the "confirm" button, the system still data as required to prior to knife knife complement values, with don't admit new to complement values, with his sword at this time if use this dao play knife events appear easily processed.
Figure 1 data show
Again as in the "worldwide" choose "the handwheel way" mode, the system will be asked to confirm the X axis and Z axis, if not confirmed, the rest are still in previous direction to move, easy to cause the tool post wrong move, play knife happens.4, G54 ~ G59 zero bias and FANUC system
In the operation of modern numerical control system, people often use a zero offset in G54 ~ G59 instructions to set the workpiece zero point position in the machine tool coordinate system (workpiece zero based on machine zero offset).Whether to use the tool compensation should be paid attention to using this method, the knife repairing value set in which points as a reference point for setting.If the machine origin from the displacement of the workpiece is knife repairing value, is to use the zero offset instructions coordinate positioning error will occur and bring dangerous operation.So once USES G54 such as zero offset instructions should be paid attention to in operation should be used in a timely manner after instructions to cancel the zero offset can be set.
In FANUC system, in the same way, there is "location", "location shift" refers to the procedures, cutter knife repairing, workpiece coordinate system, such as numerical constant, hypothetical artifact for translation, namely equivalent of workpiece coordinate system moving in the opposite direction.Do not use this method can not move in the blank, the reconstruction of coordinate system under the situation of many pieces of processing.Cancelled after using the "location shift" should be paid attention to in its value, otherwise in unwitting circumstance, other operators to operate the machine is easy to appear the workpiece coordinate system error positioning, etc., play knife occur easily, cause safety accidents.
5, cutting tool abrasion as set
Tool wear refers to the connection with the good dao, establishing good dao after filling value, after cutting tool wear, the wear a small value of knife in the cutting tool wear make up.Here suggest blade wear abrasion value can be put in corrected, but the tool length compensation value should be on the cutting tool length compensation.Because in a program such as specified in instructions, knife number, program to execute commands in knife, then the tool length compensation.And tool wear make up, to the contrary, program execution tool wear corrected first, tool change after operation.If wear as too big, easy to hit tool in machine tool worktable.
6, CNC milling machine, machining center Z axis value test
Now most of nc machine tool with a graphical check function, but more check for 2 d graphics.In CNC milling machine, machining center only to check of the X axis and Y axis graphics, Z axis value cannot graphics.So I can't think, is the right graphics program right, still need to test values of Z axis, the use of G00 or G01, G02 order for inspection, so as to avoid an accident.
7, Siemens system program for processing
Figure 2 program choice
In Siemens system for parts processing, need to choose corresponding program name, if the operator only after click to program by "open" button, as shown in figure 2, the display area workspace to just open the program, but still in the top right corner shows for the last time the automatic cycle processing the selected program, if at this time in accordance with the "cycle start" command, the processing procedures as shown in the top right corner, rather than just opened to processing program with the commonly used Windows operating system (this habit differ), and appear error processing, and even cause safety accidents.
Operation is operator clicked on the correct processing program, to be prepared in accordance with the "select" button to confirm the program choice.
