New Japanese CNC milling machine when imported to Vietnam, its price is still relatively high, while old Japanese CNC milling machinehas the advantage of low cost and accuracy, which also allows processing products with high density. acceptable error. The old CNC milling machines, after being imported, will still run for about 10 years (depending on the duration of the machine’s production), again liberating the labor force that does not require a high level of skill, mainly by programmers and manufacturers. machining accuracy, machine tolerances that are finely machined accuracy
When I go to buy new CNC milling machines, I don’t care much because there is a warranty and replacement parts, but when I buy a dump machine, I don’t notice that I can play with an iron that always won’t work, waste of money and waste of gas,..
How is the experience of buying used Japanese CNC milling machines?
– The first thing is to observe whether the size, industrial design, system design is beautiful? Mechanics seen with the naked eye are there all the accessories ? Has the machine been repainted or is it still original? The machine has been beaten back to Vietnam for a long time, if it is too long, it should not be bought because the outdoor storage yards are mainly covered with tarpaulin.
– Next, it is necessary to distinguish the cutter head using BT32, BT40, 45 or BT50 machine BT32.40 machine weight m=3-4 tons, BT 45.50 m>6 tons. Depending on the job requirements, we choose a large or small machine based on the size of the table and the BT tool head, and the spindle motor power. Table size <=420x800x450 usually uses BT40 head, 520x1100x550 size usually uses BT50 head.
– After asking the weight, size of the table, the manufacturer, the BT knife holder, we observe how old the machine is, the motor controls the XYZ axes, paint the engine’s bottom black, yellow, red . From here see if there is an engine replacement. Note machine <1981;1985 : red ass engine. The structure depends on the color, but the electric motor type is DC or AC. Distinguish that machine NC,3000c, 3M, 6M……type NC and 3000c manufactured before 1980 when purchased this type cannot transmit data from DNC computer, extremely rare component failure always only input commands Manually enter the device memory. The 3M type can transfer the form from the computer into the memory of the CNC machine and control each 120kb transmission, the G_CODE processes are too long to be cut many times. Machines from the 6M generation onwards are generally not much different from the current high-end machines that can transmit DNC carefree running day and night. Therefore, it is recommended to buy a device from 6M or later.
– Next, you need to see if this machine has a mechanical counterbalance, For example, if the locomotive weighs 1 ton, the back part connected by a counterweight chain also weighs about 1 ton. The advantage of counterweights is that the machine head is always balanced in the event of a sudden power failure that does not cause the Z-knife (knife to lower Z) machines that do not have a counterweight when the power is lost or the knife is eaten into the workpiece. mechanical damage to the knife (although there is a Z engine brake, it does not work).
– If it is a large milling machine with large cutting force, high machine rotation usually follows a part of the air conditioner that cools the oil pump back to the main shaft (pumps and returns the oil continuously and is cooled like an air conditioner). gas). This device is usually not mounted directly on the machine but is wired in the form of a tube to return and pump the oil. Therefore, if it is lost or the seller hides it, it must also fix this point.
– See if there are additional commands on the keyboard control buttons to refer to forcible intervention during the transmission. The more you have, the better. For example: we run G0 to 100%, the step of the table is 3000mm/min but there is an intervention button we leave 50% now when the machine runs to the G0 command it only runs as fast as 1500mm/min, similarly the buttons control spindle rotation, cutting feed,..
– Basically the mechanical observation is like that, then proceed to turn on the circuit breaker and wait to see if the screen is blurred, see an error (alarm), if the error is, the factory must fix it. Run the G0 commands to run as fast as possible to see if there is any rattling, the machine runs the shafts as quietly as possible. Switch back to the handle to turn the axes to see if the table is moving smoothly and without jerks, then bring the counter to measure the // of the table. We have witnessed a lot of machines that have to be milled because they don’t / / flat milling, they suffer because during transportation, there is a broken crane chain, falling of the machine.
– Turn on the spindle with the M3 command, use the odometer to check the runout of the tool head, see the maximum speed of the spindle.
– Check to see if it is possible to change the tool automatically, if the machine has many cutters but cannot change the tool automatically, it is possible that the main shaft motor inverter has been damaged and has been replaced with another inverter, including the spindle motor. .
– See if the machine is configured with a stationary Z-axis table lift or a stationary table that moves XY head up and down according to Z-axis control. See if both the input and output systems in the Y axis (this type of machine Hithchi seiki usually do) this kind of thing is not very optimized.
– Should buy XY table milling machine with XY head Z axis moving up and down.
– The main CNC machine manufacturers in Vietnam are: Mori seiki, Hitachi seiki, Okuma Hawa, Enhsu, Machino, Hamai, Roku roku, Okuma, ..
– CNC has many types and manufacturers, but commonly used control systems: Fanuc, Mitsubishi, Siemens; In addition, there are control systems: Fagor, HEIDENHAIN, Fadal, ..
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