NEWS CENTER
1. The influence on cutting temperature: cutting speed, feed rate, back feed;
The influence of cutting force: the amount of cutting, feed rate, cutting speed;
Effect on tool durability: cutting speed, feed rate, load.
2. When the amount of cutting tool is doubled, the cutting force is doubled;
When the feed rate is doubled, the cutting force increases by about 70%.
When the cutting speed is doubled, the cutting force decreases gradually.
That is to say, if G99 is used, the cutting speed increases, and the cutting force does not change much.
3. The cutting force and cutting temperature can be distinguished according to the discharge of iron chips.
4. When the practical value X and the diameter Y of the drawing is greater than 0.8, the concave arc of the car, the sub-deflection Angle of 52 degrees of the turning tool (that is, the commonly used blade of 35 degrees of the main deflection Angle of 93 degrees of the turning tool) of the car out of the R in the starting position of the local may wipe the knife.
5. Temperature represented by the color of iron filings:
White is less than 200 degrees
Yellow 220-240 degrees
Dark blue 290 degrees
Blue 320-350 degrees
Purple black is greater than 500 degrees
Red is more than 800 degrees
6.FUNAC OI MTC generally acquiesces in G instruction:
G69: Revocation of the G68 rotation frame instruction
G21: Metric standard input
G25: Spindle speed shake detection is disconnected
G80: Fixed cycle revocation
G54: Coordinate system acquiescence
G18: ZX plane selection
G96 (G97) : Constant linear speed control
G99: Feed per turn
G40: Tip compensation revocation (G41 G42)
G22: Storage trip detection is connected
G67: Macro program modal call revocation
G64: is the instruction of the connection way in the early Siemens system, which is used for the roundness of the reverse circle with axial tolerance. G64 is the original instruction of G642 and Cycle832 in the later period.
G13.1: Polar interpolation mode revoked
7. External thread is generally 1.3P, internal thread is 1.08P.
8. Thread speed S1200/ pitch * safety factor (generally 0.8).
9. Manual tool tip R compensation formula: from the bottom to the car chamfering: Z=R* (1-tan(a/2)) X=R(1-tan(a/2))*tan(a) from the top to the car chamfering will be changed from minus to plus.
10. Each 0.05 increase in feed will reduce the speed by 50-80 RPM. This is because the drop in speed means that the tool wear decreases, and the cutting force increases slowly, and then compensates for the increase in cutting force and temperature caused by the increase in feed.
11. Cutting speed and cutting force on the tool is very important, cutting force ambassador of the main reason for tool collapse.
The connection between cutting speed and cutting force: Feed unchanged when cutting speed faster, slowly reduce the cutting force, cutting speed faster together can make the faster tool wear, the cutting force is more and more big, the temperature will be higher and higher, when the cutting force and internal stress to the blade can't bear, will the landslide knife (of course there is attack by change of stress and temperature drop in hardness, etc).
12. In CNC machining, the following points should be paid special attention to:
(1) about the current our country's economy is generally selected numerical control lathe was general three-phase asynchronous motor through continuously variable frequency converter is complete, assuming no mechanical reduction, often at low speed main shaft output torque is insufficient, assuming that cutting load is too large, a brief stuffy car, but some machine tool with a pinion gear on the very good deal with the problem;
(2) as much as possible to make the tool can end a part or a shift of the operation industry, large finishing should pay special attention to the center to prevent midway tool change to ensure that the tool can be a machining end;
(3) when using CNC turning threads, the high speed may be selected to complete the high quality and efficient production;
(4) Use G96 whenever possible;
(5) the basic concept of high speed processing is to make the feed beyond the heat conduction speed, and then the cutting heat is discharged with the chip to make the cutting heat and the workpiece isolation, to ensure that the workpiece does not heat up or less heat up, therefore, high speed processing is to select a high cutting speed and high feed matching together to select a small amount of back feed;
(6) pay attention to the compensation of tool tip R.
13. Frequent vibration and knife collapse in the groove:
All all of our reasons for this are rigid not variable cutting force and cutting tool, cutting tool out of the shorter length, the Angle is smaller, the area of the blade is larger, the better rigidity, can with the cutting force, but the width of the slot cutter can withstand the greater the cutting force will increase, but its cutting force also increases, rather small slot knife it can withstand the force is small, but its cutting force is small.
14. Reasons for the attack of vibration in the groove:
(1) the extension length of the tool is too long, and the backward rigidity decreases;
(2) the feed rate is too slow, resulting in a larger unit cutting force and resulting in a large amount of vibration, the formula is: P=F/ back cutting volume * F P is the unit cutting force F is the cutting force, in addition, too fast rotation speed will vibrate the tool;
(3) the machine tool is not rigid, that is, the tool can bear the cutting force, and the machine tool can not bear, to put it bluntly, the machine tool car does not move, the general new bed will not appear this kind of problem, the bed of this kind of problem is either old, or often encountered machine tool killer.
15. When a car goods, found that standards are also good at first, but made a few hours later found attacks changed and standard unsafe reason maybe is just at the beginning because the knife is new, so the cutting force is not big, but after a period of time, tool wear, cutting force, led to the workpiece on the chuck shift, so the standard old run and not safe.
16. When using G71, the values of P and Q cannot exceed the sequence number of the whole program, otherwise an alarm will appear: the instruction pattern of G71-G73 is incorrect, at least in FUANC.
17. There are two patterns of subroutines in FANUC system:
(1) The first three of P000 0000 refer to the number of cycles, and the last four refer to the program number;
(2) The first four digits of P0000L000 are the program number, and the three digits after L are the number of cycles.
18. If the starting point of the arc remains unchanged, and the ending Z direction is offset by a mm, then the bottom diameter of the arc is offset by a/2.
19. The drill does not grind the cutting groove when drilling deep holes to facilitate chip removal.
20. It is assumed that the tool holder is used for drilling, the drill bit can be rolled, and the hole diameter can be changed.
21. In the stainless steel central hole, perhaps when the stainless steel hole is punched, it is necessary for the bit or the center of the central drill to be small, otherwise it will not move. When drilling with cobalt drill, the groove is not grinded to avoid the bit annealing in the process of drilling.
22 according to the process of the material is generally divided into three kinds: a material, two goods, the whole bar material.
23. When the ellipse appears in the thread of the car, it may be that the material is loose. It is OK to use a tooth knife to cut more knives.
24. In some systems where you can input macro programs, you can replace the subroutine loop with macro program filling, which can save program numbers and prevent a lot of trouble.
25. If a drill bit is used for reaming, but the jump of the hole is very large, then a flat bottom drill can be used for reaming, but the twist drill must be short to increase the rigidity.
26. In the drilling machine, if the drill is drilled directly, the aperture can appear error, but if the reaming standard in the drilling machine is generally not run, such as using a 10MM drill in the drilling machine for reaming, then the aperture of the expansion is generally about 3 wire tolerance.
27. At the time of the car hole (through hole), try to make the chips roll continuously and then discharge from the tail. Key points of the chip roll: First, the orientation of the knife should be properly placed high, second, the appropriate Angle of the blade, the amount of the knife and the feed, remember that the knife can not be too low or simply break the chip, assuming that the auxiliary Angle of the knife is large, even if the chip will not stick the cutter bar, assuming that the auxiliary Angle is too small, the chip will be stuck after the chip is broken.
28. The greater the cross section of the knife bar in the hole, the more difficult it is to vibrate the knife. There can be a strong rubber band on the knife bar, because the strong rubber band can play a certain role in the adsorption of vibration.
29. In the copper hole, the knife tip R can be appropriately larger (R0.4-R0.8), especially in the taper under the car, iron parts may be nothing, copper parts will be very jagged.
Machining center, CNC milling machine tool compensation
Machining center, CNC milling machine CNC system, tool compensation function including tool radius compensation, Angle compensation and length compensation tool compensation function.
(1) Tool radius compensation (G41, G42, G40) Tool radius value is stored in the memory HXX in advance, XX is the memory number. After performing the tool radius compensation, the numerical control system takes the initiative to calculate and make the tool take the initiative to compensate according to the calculation result. Left tool radius compensation (G41) refers to the left side of the movement direction of tool inclination programming machining path (as shown in Figure 1), and right tool radius compensation (G42) refers to the right side of the movement direction of tool inclination programming machining path. The revocation tool radius compensation uses G40, the revocation tool radius compensation also can use H00.
Numerical control technician practice tips: in the use of attention should be paid to: the establishment and cancellation of knife compensation, that is, the use of G41, G42, G40 instructions of the program segment is necessary to use G00 or G01 instructions, not to use G02 or G03, when the radius of the tool compensation to take a negative value, G41 and G42 function exchange.
Tool radius compensation B function and C function two forms of compensation. Because B cutting tool radius compensation function, calculated the knife repairing only under this section of the program cannot handle the transition between the procedures section, request will be treated as workpiece induction into the rounded transition, therefore the workpiece Angle manufacturability owe good, C function cutter radius compensation can take the initiative to deal with two transfer procedures section cutting tool center orbit, can be completely according to the workpiece to programming, Therefore, modern CNC CNC machine tools are simply the use of C function tool radius compensation. At this time, it is required that the following two program segments to establish the tool radius compensation program segment must have the displacement instructions (G00, G01, G02, G03, etc.) that specify the compensation plane, otherwise the correct tool compensation cannot be established.
(2) Angle compensation (G39) The intersection of the two planes is an Angle, which may occur over cutting and lead to processing errors. Angle compensation (G39) can be used to deal with it. Note when using the included Angle compensation (G39) instruction. This instruction is non-modal and only valid in the program section of the instruction. It can only be used after G41 and G42 instructions.
(3) tool length bias (G43, G44, G49) using the tool length bias (G43, G44) instruction can not change the program and at any time to compensate the tool length change, the compensation amount is stored in the memory by the H code instruction. G43 indicates the addition of the compensating amount in memory to the end coordinate value of the program instruction, G44 indicates the subtraction, and revokes the cutter length bias by either G49 instruction or H00 instruction. In program segment N80 G43 Z56 H05 and, if the median memory value of 05 is 16, then the end coordinate value is indicated as 72mm.
The value of the compensation amount in the memory can be stored in the memory in advance by MDI or DPL, or indicated by the program segment instruction G10 P05 R16.0 that the compensation amount in the No. 05 memory is 16mm.