What is dimensional accuracy in a laser cutting machine?

I face the same question from many buyers. They need tight parts. They need repeatable sizes. They also need simple answers. I keep it clear. Dimensional accuracy tells us how close the actual cut part is to the CAD size, in any production shift.

Dimensional accuracy in fiber laser cutting means how close the part is to the design size. In most industrial jobs, I hold ±0.05 mm with the right machine, stable motion control, tuned parameters, and clean optics. I keep accuracy stable with routine calibration and quick checks.

I do not sell guesswork. I sell predictable parts. So I frame accuracy in simple terms. I link it to beam quality, motion, thermal control, and process discipline. When I do that, customers see fewer rejects and fewer assembly issues. They also see shorter lead times.

What is the dimensional accuracy of laser cutting?

Many teams ask me if "±0.05 mm" is real. I say yes, if the stack is right. I focus on beam mode, rigid mechanics, encoder feedback, and stable cutting parameters. I also keep the table clean. Chips and dross can distort the sheet and ruin accuracy.

Dimensional accuracy for fiber laser cutting is typically ±0.05 mm on well-tuned machines. I can hold ±0.03 mm on small parts and short runs with stable temperature and good fixturing. I track drift with daily calibration, warm-up cycles, and cut tests that match real jobs.

Dive deeper

When I talk about accuracy, I break it into machine, process, and environment. I also look at how tolerance stacks up across a full sheet. Static numbers mean little if the sheet moves, heats, or bows.

What shapes real accuracy

• Machine: Beam quality (M2), linear guides, ball screws or rack-and-pinion, servo tuning, encoder resolution.
• Process: Nozzle centering, focus offset, gas pressure, pierce routine, lead-in strategy, kerf compensation¹.
• Environment: Sheet flatness, workholding, thermal rise, shop temperature, vibration.

Practical tolerance bands by case

Case	Material	Thickness	Typical accuracy	Notes
Prototype small parts	SS	1.5 mm	±0.03 mm	Short runs, tight thermal control
Production panels	MS	3.0 mm	±0.05 mm	Stable after warm-up
Thick plates	MS	12 mm	±0.10 mm	Kerf taper more visible
Non-flat sheets	Al	2.0 mm	±0.08 mm	Use pins or vacuum
Long parts >1000 mm	MS	4.0 mm	±0.10 mm	Thermal expansion accumulates

How I hold ±0.05 mm at Kirin Laser

• I use high-brightness fiber sources with stable power. This keeps the kerf consistent.
• I use rigid frames, ground rails, and tuned servos. This keeps the path true.
• I center the nozzle and check the focus height before each shift. I use a gauge tool for speed.
• I set pierce, power, duty, and speed per thickness. I validate with a small coupon.
• I add kerf compensation in the CAM. I verify by cutting a 20 mm square and a 20 mm hole.
• I run a 10-minute warm-up path on cold mornings. This reduces drift.
• I record daily cut tests. I adjust only one parameter at a time. I avoid chasing noise.

A short story says why this matters. One aerospace client saw poor fit in rib assemblies. Holes were oval. Tabs were tight. They upgraded to a high-precision fiber laser². I set a new cut library, added kerf comp, and locked a warm-up routine. They hit ±0.05 mm and fit issues stopped. Assembly time dropped, and so did rework.

How accurate is a laser cutting hole?

Holes challenge every machine. The path is short. Heat is high. The kerf can taper. I treat holes with care. I adjust lead-in, micro tabs, and speed to stabilize the roundness and the size.

Hole accuracy in fiber laser cutting is typically ±0.05 mm for holes over 1.5 mm. For small holes near thickness, I use micro-cycles, lower power, and a special lead-in. I often ream critical holes or use a punch-laser combo for the tightest fits.

Dive deeper

Holes bring three problems: out-of-round shape, taper from top to bottom, and heat-affected oversize. I handle these with path planning, parameter control, and design rules.

Key controls for round holes

• Lead-in: I set a short tangent lead-in³ outside the final hole. I avoid starting on the hole edge.
• Pierce: I use pre-pierce for thick plate, then I cut at steady state.
• Speed and power: I lower power and speed for small holes to reduce taper.
• Assist gas: I pick nitrogen for stainless and aluminum to avoid oxide; oxygen for mild steel if needed.
• Micro-cycles: I add a short dwell or multi-pass for holes near thickness.
• Kerf comp: I bias the hole undersize by 0.02–0.05 mm, then test and tune.

Hole size rules I use

Material	Thickness	Minimum hole size	Expected tolerance	Notes
SS	1.0 mm	1.0 mm	±0.05 mm	Nitrogen cut, sharp edge
MS	3.0 mm	1.5 mm	±0.06 mm	Oxygen cut, slight oxide
Al	2.0 mm	1.0 mm	±0.06 mm	Nitrogen cut, avoid burr
MS	10 mm	5.0 mm	±0.10 mm	Consider drill or ream after

I keep a simple loop for validation. I cut a test coupon with a matrix of holes from 1 mm to 10 mm. I measure each with pin gauges. I update the kerf table for each thickness and gas. I lock those into the job card. This turns hole accuracy into a repeatable process, not hope.

For tight fits, I mix processes. I cut the hole 0.1–0.2 mm undersize on the laser. Then I ream or countersink on a drill stand. This still saves time because the laser does all the complex shapes. The ream gives the fit class, like H7, with no burr.

I also watch circularity. I keep the motion loop tight with high encoder resolution. I avoid tiny segments in the CAM⁴. I use true arcs where I can. Smooth toolpaths give round holes. Choppy toolpaths do not.

Why is my laser cutter not accurate?

When someone calls me about poor accuracy, I check a short list first. The cause is often simple. The fix is often fast. I do not change ten things at once. I test and move step by step.

Most accuracy problems come from focus height, nozzle misalignment, dirty optics, bad sheet support, or thermal drift. I fix these with a focus gauge, a nozzle centering test, clean lenses, flat slats, stable gas, and a warm-up routine. I verify with a 20 mm square and hole test.

Dive deeper

I split accuracy issues into geometry, process, and environment. I map symptoms to likely causes. Then I confirm with a quick cut-and-measure test. This keeps me from guessing and wasting time.

Symptom to cause map

Symptom	Likely cause	Quick check	Fix
Parts oversize	Wrong kerf comp	Cut 20 mm square	Update kerf table
Holes undersize	Taper / heat	Pin gauge set	Reduce power, slow speed, micro-cycle
Oval holes	Motion lag	Circle test path	Servo tune, use true arcs
One axis drift	Backlash / belt	Cut square and measure	Tighten/replace belt, check preload
Burr on one side	Nozzle off-center	Paper dot test	Center nozzle, change tip
Edge rough	Dirty lens	Visual check	Clean/replace lens
Warp on long cuts	Thermal rise	Infrared probe	Alternate path, pause between cuts
Random size shift	Gas pressure spike	Gauge log	Regulator and filter check

My standard diagnostic routine at Kirin Laser

1. Warm up the machine with a simple path for 10 minutes.
2. Check shop temperature. Keep it steady within a small band.
3. Clean the collimator and focus lens. Inspect for pits.
4. Center the nozzle using a low-power circle test on tape.
5. Zero the focus with a feeler gauge or auto-height sensor calibration.
6. Verify gas type and pressure. Purge lines if water or oil is present.
7. Cut the 20 mm square and 20 mm hole on the job material and thickness.
8. Measure with calipers and pin gauges⁵. Record results.
9. Update kerf comp⁶. Recut and confirm. Lock the parameters.

I also teach teams to watch slats and sheet support. Bent slats lift the sheet. That changes focus mid-cut. I rotate or flip slats before they get bad. I add simple pins to hold large sheets flat. For thin aluminum, I use more supports to kill flutter.

Motion matters too. If I see axis lag, I run a circle-square test and plot error. I tune servo gains or replace belts if they slip. I avoid heavy acceleration on tiny features. Smooth wins.

Above all, I keep maintenance simple and regular. Small checks every day beat big fixes every month. That is how I keep parts tight in real production.

Which material should never be cut by laser?

I get this question a lot. Safety comes first. I always check the material list before I accept a job. Some materials release toxic gas. Some damage optics. Some catch fire. I never risk my team for one order.

I never cut PVC or vinyl because they release chlorine gas and damage optics. I avoid PTFE (Teflon), ABS, and fiberglass due to toxic fumes. I avoid beryllium copper and magnesium because of health and fire risks. For fiber lasers, I cut metals, not organics or unknown plastics.

Dive deeper

I set clear rules for my team and for our partners. I also teach customers why these rules exist. The reasons are safety⁷, machine health, and product quality. The list is short, but the impact is large.

Materials I never cut at Kirin Laser

Material	Why not	Risk
PVC / Vinyl	Releases chlorine gas, corrodes optics and mechanics	Toxic fumes, machine damage
PTFE (Teflon)	Releases toxic fluorinated gases	Health hazard
ABS	Melts and emits cyanide-bearing fumes	Toxic fumes, poor edge
Fiberglass (GFRP)	Glass and resin burn and abrade optics	Dust, toxic resin smoke
Carbon fiber with epoxy	Resin fumes and conductive dust	Health and electrical risk
Beryllium copper	Beryllium dust is highly toxic	Severe health hazard
Magnesium	High fire risk with sparks	Fire hazard
Unknown plastics	Unknown fillers and fumes	Unpredictable risk

Fiber laser scope and best practice

Fiber lasers are best for metals like mild steel, stainless steel, and aluminum. They also cut copper and brass with the right back-reflection protection and stable power control. I avoid organics with fiber lasers⁸. Their 1 µm wavelength does not couple well to many plastics or wood. The process is not clean or safe for those.

For any new job, I ask for the material spec sheet⁹. I do a small cut in a safe area. I use good extraction. I measure edge quality and burr. If something smells odd or leaves sticky residue, I stop. I do not push through unknowns.

If a customer needs plastic cutting, I guide them to CO2 lasers¹⁰, which suit many plastics, with strict safety rules. If they need one step that must be laser-safe, I propose a different method such as routing, punching, or waterjet, depending on the part.

I also train the team to watch for hidden laminates. A sheet that looks like acrylic may have PVC film. I peel any film before cutting. I also label safe stock and unsafe stock. Clear labels avoid mistakes in a busy shop.

Conclusion

Dimensional accuracy in fiber laser cutting¹¹ is a system result. I get tight parts when I align beam, motion, parameters, and environment. I treat holes with special paths and tests. I fix accuracy issues with a short, clear routine. I never cut unsafe materials. At Kirin Laser, I hold ±0.05 mm in real jobs because I control the whole stack and I keep it simple and repeatable.