CNC Machine Setup Work Instruction Example

What a CNC setup involves

A setup covers everything between the last good part of one job and the first approved part of the next: tearing down the old fixture, mounting and aligning the new one, loading and measuring tools, setting the work offset, loading and proving the program, and inspecting the first piece. Most of the risk sits in a few places. The program or drawing may be the wrong revision, a tool length offset may be entered against the wrong tool, or the work offset may be set to a point that is not the drawing datum. Any of those can scrap a run or crash the spindle.

A setup work instruction fixes the order of those tasks and puts a check at each risky point, so two setters on two shifts set the machine the same way. It is written for one machine type or cell and reused for every job on it. The values that change job to job, such as tool list, fixture location and datum, live on the job’s setup sheet, and the instruction tells the setter where to find them and how to check them.

Setup sheet or work instruction?

The setup sheet answers “what” for one part number: which fixture, which tools in which pockets, which datum, which program. The work instruction answers “how” for every part on that machine: the method, the checks and the sign-offs. Keeping them apart means a new job needs a new setup sheet, not a rewritten instruction. Cutting data belongs on the setup sheet or in the program, set by the programmer. The speeds and feeds calculator is a starting point for that, not a substitute for the programmer’s values.

Example: Vertical Machining Center Job Setup

Example This work instruction is for Example Manufacturing Co., a fictional contract machine shop. Document numbers, tolerances and override settings are example values, not recommendations. Use the values on your own setup sheet, machine manual and procedures.

Download this example (.docx)

Tools, materials and PPE

• Job packet: traveler, drawing, setup sheet and program, at the revisions on the traveler
• Dial test indicator with magnetic base
• Tool presetter or spindle probe
• Calibrated gauges listed on the setup sheet
• Safety glasses; cut-resistant gloves for handling cutters only
• Hoist or lift assist for fixtures over 16 kg (example value)

Steps

1. Check the job packet. Compare the revision on the drawing, setup sheet and program header with the traveler.
   Key point: All four revisions match. If any differs, stop and call the lead before touching the machine.
   Reason: A program or drawing at the wrong revision can turn out a whole run of parts that meet the wrong requirement.
2. Clear and clean the machine. Remove the previous fixture and any tools not on the new setup sheet. Clean chips from the table, T-slots and fixture seats.
   Key point: Return removed tools to the crib, tagged with the job they came from.
   Reason: A chip under a fixture tilts it, and every feature machined from it shifts.Safety: Put the machine in setup mode with the spindle stopped before reaching into the work envelope. Clear chips with a brush or hook, never bare hands or compressed air.
3. Mount and indicate the fixture. Clamp the vise or fixture at the location on the setup sheet. Sweep the locating face along the X axis with the dial test indicator and adjust until it is in tolerance.
   Key point: Within 0.01 mm over the jaw length (example value; use the tolerance on your setup sheet). Re-check after final clamping.
   Reason: A fixture out of square tilts every feature relative to the datums on the drawing.Safety: Use the hoist or lift assist for fixtures over the weight limit. Keep fingers clear of the clamping points.
4. Load tools and set length offsets. Load each tool in the pocket on the setup sheet. Measure each length on the presetter or with the probe and enter it in the matching offset register.
   Key point: Read back tool number, pocket and offset number for every tool. They must match the setup sheet.
   Reason: A length offset entered against the wrong tool drives the cutter into the part or fixture.Safety: Handle cutters by the holder. Remove gloves before running the spindle.
5. Set the work offset. Find the datum named on the setup sheet with the probe or an edge finder and enter it in the work offset on the setup sheet, for example G54.
   Key point: Confirm the setup-sheet datum is the same feature as the drawing datum before you touch off.
   Reason: An offset set to the wrong corner or face moves every feature by the same error.
6. Prove the program. Load the program and confirm its number and revision on the control. Run it in graphics, then dry-run it with the work offset raised in Z by 50 mm and rapid override at 25% (example values).
   Key point: Watch each tool change and approach. Keep one hand on feed hold during the dry run.
   Reason: Offset and program errors show up in air instead of in the part or the fixture.Safety: Run with the door closed and the interlocks working. Never bypass an interlock to watch the cut.
7. Cut and measure the first piece. Run the first part in single block through each new tool. Measure every characteristic on the first-piece checklist with the gauges on the setup sheet.
   Key point: Write the measured value for each characteristic, not a tick. Check gauge calibration dates first.
   Reason: Recorded values show the setup is centered in tolerance, not just inside it, and give the next setter a reference.
8. Get first-piece approval. Give the part and the filled checklist to the inspector or another authorized person for review and sign-off.
   Key point: No production parts until the first piece is signed off.
   Reason: An independent check catches errors the setter is too close to see.
9. Record and release. Write any offset or program changes on the setup sheet, sign the traveler and release the machine to production.
   Key point: Changes to the program go back to programming. Do not save edits on the control without approval.
   Reason: The next setup starts from what worked, and the program master stays controlled.

Acceptance criteria

• Drawing, setup sheet and program revisions match the traveler, initialed by the setter.
• Fixture indicated within the setup-sheet tolerance (example: 0.01 mm over the jaw length).
• Every tool, pocket and offset number matches the setup sheet.
• First piece measured on every listed characteristic, all values recorded and within tolerance.
• First-piece approval signed before production starts.

How to adapt this example

Copy the steps into the blank work instruction template, or edit the .docx above. Start from your own setup, not from this page. Watch your best setter run a job, write down what they actually do and in what order, then use the example to check you have a key point and a reason for each step. The how to write a work instruction guide covers the method.

• Name your machine type, cell and control, and change the steps that differ, such as a lathe’s chuck and turret instead of a vise and tool changer.
• Move every job-specific value onto the setup sheet and point to it from the step.
• Match the first-piece step to your quality plan. Some customers require a first article inspection as well; use a first piece inspection checklist to record the result.
• Add photos of the fixture seat, offset screen and indicator setup. The visual work instruction template gives each step a photo, key point and reason.
• Keep maintenance tasks such as way-cover or spindle work out of this instruction. Those need your lockout/tagout procedure.
• Have a setter who did not write it run a job from it, and fix every place they hesitate.

Related tools for setup

The tap drill chart helps when checking drill sizes on the tool list, and the unit converter helps when a drawing and a machine work in different units. To turn this instruction into a one-page sheet at the machine, see job aid vs work instruction vs SOP.

Common mistakes

• Writing tool lists and offsets into the instruction. Put job-specific values on the setup sheet and keep the instruction about method, so one instruction serves every job.
• Checking the program number but not the revision. Compare the revision in the program header with the traveler every setup.
• No read-back of offsets. Make tool, pocket and offset number a read-back check, by the setter or a second person.
• Skipping the dry run when the job ran last week. Prove the program every setup. Tools, offsets and fixtures may have changed since.
• First-piece checklist with ticks instead of values. Record measured values so a reviewer can see where the setup sits in the tolerance.
• Safety notes in a block at the top. Put each safety callout on the step where the hazard occurs.

Frequently asked questions

Sources

1. ISO 9001:2015 Quality management systems — Requirements (clause 8.5.1, control of production), ISO
2. 29 CFR 1910.212, General requirements for all machines, U.S. Occupational Safety and Health Administration
3. Machinery’s Handbook, Industrial Press

See also

• How to write a work instruction (Work Instructions pillar)
• Blank work instruction template (.docx)
• Visual work instruction template
• First piece inspection checklist
• Speeds and feeds calculator
• Torque sequence work instruction example
• MIG welding setup work instruction example
• Packaging and labeling work instruction example
• Cleanroom gowning work instruction example