How to Run a Doosman CNC Machine

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  Key takeaways
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  Pre-run checks on a Doosman CNC machine
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  Workholding and zero point setup
• 4
  Tool offsets and work coordinate systems
• 5
  What goes wrong in the first hour
• 6
  Step by step: running a Doosman CNC machine
• 7
  Choosing setup method by part and tolerance

A Doosan machine built for production work has a cast iron base and a Fanuc or Doosan control. The iron does not care how you approach the setup, but the control will reject anything it does not understand. Before you press Cycle Start, confirm three things: the machine is thermally stable, the offsets match the physical tools, and the fixture holds the part without flex. Skip any one and the first part comes out wrong.

Thermal stability matters more than most operators admit. A cold machine and a warm machine differ by 10-20 μm over the Z axis. On a part with a ±0.02 mm tolerance that is fine. On a ±0.005 mm bore it is not. Run the spindle at 25-50% of its maximum speed for 10-15 minutes with the coolant on. That warms the spindle housing and the ballscrews without loading the ways.

Check the way lube reservoir and the air pressure before anything else. Low air pressure trips the tool changer mid-cycle. Low lube oil scores the linear guides, and that repair costs far more than a five-minute check. Doosan mills typically want 0.5-0.6 MPa at the regulator. Confirm the spindle chiller is running if your machine has one.

Finally, verify the program at the control. Compare the file name against the job traveler. A program from the previous job left loaded in memory is one of the most common causes of a crash in small shops. Select the right program, check the tool list against the setup sheet, and only then load the part.

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  Warm up 10-15 minutesSpindle at 25-50% max speed, coolant on, no cutting.
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  Check air and lube0.5-0.6 MPa at the regulator; confirmed oil in the way lube tank.
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  Match program to travelerVerify file name, revision, and tool list before loading stock.

Where you hold the part decides how it cuts. A vise with 3 mm of jaw engagement on a 100 mm tall block will lift and chatter. Aim for at least one third of the part height in the jaws, and seat the part on parallels so it sits flat. Tap the part down with a dead blow mallet before tightening. That seats it against the parallels and removes the air gap that ruins a facing pass.

For plate work, vacuum chucks and magnetic chucks win on thin parts where a vise would bow the material. For a 6 mm aluminum plate, a vise closes the part and the top face comes out convex. A vacuum table holds it flat. The tradeoff is grip strength: light radial cuts only, and no heavy shoulder milling.

Soft jaws machined to the part profile are the standard answer for round or irregular parts. Bore the jaws to 0.05 mm under the part diameter for a press fit by hand, or cut a step for a locating shoulder. Record the jaw bore size in the setup sheet so the next run does not need to re-indicate.

Zero point on a Doosman CNC machine usually lands on a corner or a bore of the fixture. Touch off with a 10 mm edge finder at 600-800 rpm, or use a 3D taster for ±0.01 mm repeatability. A coaxial indicator is slower but reads directly to 0.01 mm and does not need spindle rotation during the touch. Whichever tool you use, write down which face and which corner you zeroed on. Ambiguity here is where scrap starts.

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  Jaw engagementOne third of part height minimum.
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  Seat on parallelsDead blow tap before final tightening.
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  Soft jawsBore 0.05 mm under part diameter for hand press fit.

Tool offsets tell the control where the cutting edge sits in space. Get them wrong and the machine either cuts air or buries the tool in the fixture. Set length offsets with a tool presetter offline if you have one. If you set them on the machine, touch each tool to a known reference surface, such as the top of a 50 mm gauge block on the table, and enter the value in the length register. H01 pairs with T01, H02 with T02, and so on.

Do not assume the pairing. Some shops use H numbers that match the tool number; others use a separate set. Read the setup sheet. A mismatch between T and H is a classic crash: the control picks up the length of a different tool and drives the current tool into the part. If the machine has a tool measurement arm, use it, but verify one tool by hand against a gauge block before trusting the arm on the whole set.

Diameter offsets matter on any contour with a tolerance. Enter the actual measured diameter of each cutter, not the nominal size. A 12 mm end mill that measures 11.96 mm cuts a different slot than the CAM file expects. Update the D register when you change a tool, and note the change on the setup sheet.

Work coordinate systems define the program zero on the physical part. G54 is the default. G55 through G59 are available for multiple vises or a second operation on the same table. Touch off the zero corner, enter the X and Y values in the G54 page, and confirm the Z value against the gauge block. Then, with the spindle stopped, jog to X0 Y0 and look at where the tool sits relative to the part corner. Eyeballing this takes ten seconds and catches a decimal point error before it becomes a crash.

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  T and H must matchConfirm on the setup sheet before cycle start.
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  Measure real diametersEnter measured values, not nominal, in the D register.
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  Verify X0 Y0 visuallyJog to zero with spindle stopped and check the corner.

Most crashes in the first hour come from three sources: a wrong offset, a fixture that moves, or a program from the previous job. The control will happily run all three. Watch the distance-to-go display on the first rapid move. If the number looks larger than the clearance you expect, stop the cycle. That habit catches more errors than any checklist.

Chatter on the first cut usually means the part is not seated or the tool is too long for the diameter. Reduce the stick-out where you can. On a 12 mm end mill, keep stick-out under 40 mm for anything beyond a light finishing pass. If the tool is already short and the part still rings, add a support under the overhang or switch to climb milling with a lighter radial engagement.

Alarms on a Doosman CNC machine are usually specific. An overtravel alarm means the axis hit a limit, often because the work coordinate is off by a large amount. A tool change alarm usually points to air pressure or a stuck tool. Write down the alarm number and the axis before you clear it. The same alarm will come back if you only reset the control.

Spindle load tells you whether the cut is reasonable. On aluminum, a 12 mm three-flute end mill at 8,000 rpm and 1,500 mm/min should sit well under 50% load in a light roughing pass. If the meter spikes past 80%, reduce feed before the tool breaks. On steel, keep the load steady rather than high. A fluctuating meter means the chip load is inconsistent, which usually traces back to a loose setup.

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  Watch distance-to-goStop the cycle if the first rapid looks wrong.
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  Record alarm numbersNote the axis before clearing the alarm.
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  Keep stick-out shortUnder 40 mm for a 12 mm cutter in roughing.