The diagnostic path is part geometry → Burny 10 LCD command → axis motion → torch position → arc and gas process → finished kerf. Follow that path in order. For the stated job—a 1/4 in hole through 0.134 in 316L stainless steel—the calculated diameter-to-thickness ratio is about 1.87:1. Heat enters a very short contour quickly, so delayed motion, cornering slowdown, or excess overlap can create dross before a gas change has any chance to help.
Where does the cutting path stop behaving correctly?
Separate the request from the delivered process. The program requests a circular path and feedrate. The controller converts that request into axis motion. The torch system establishes the arc and gas flow. The plate then responds to the delivered heat and momentum. A defect at the hole cannot identify which stage failed by itself.
| Path element | Reading or observation | Meaning | Next check |
|---|---|---|---|
| Part geometry | Hole diameter, lead geometry, entry point, direction | A correct contour rules out an obvious programming error | Physical setup |
| Controller command | Programmed feed and motion trace | The command may be correct even when the axes never reach it | Actual motion |
| Axis motion | Velocity through entry, circle, and exit | Acceleration or contour limits can prolong heating | Arc process |
| Arc process | Pierce completion, arc stability, kerf direction, dross location | Distinguishes excess heat from incomplete material ejection | Controlled test cut |
Is the physical layer stable before motion begins?
Layer one first. Inspect the torch consumables, orifice condition, alignment, gas delivery, torch-to-work distance, work connection, and plate surface. A damaged or contaminated orifice deflects the arc and can make a correctly programmed circle appear oval or tapered. Unstable gas delivery changes the force ejecting molten metal from the kerf.
Confirm that the installed consumables, current range, and gas selection belong to the same process-chart combination for the Interlogic/Inova torch. Record the actual configuration rather than relying on the controller recipe name. The installation uses an H17 mixture, but that label alone does not define whether the mixture, pressure, flow, consumables, and current form an approved cutting combination for 316L at this thickness. Read those values from the torch process documentation and gas supply identification.
Reject the physical branch before tuning motion if the arc wanders, consumables show asymmetric wear, gas flow is unstable, or the work connection produces an erratic arc. Tuning feedrate around an unstable arc only hides the cause for one coupon.
Does the torch reach cutting speed on the circle?
A 1/4 in circle has a circumference of approximately 0.785 in. That short path gives the axes little distance to accelerate, settle, and decelerate. Programmed feedrate is therefore not the decisive measurement; actual contour velocity is.
| Motion reading | Interpretation | Action |
|---|---|---|
| Actual velocity closely follows the command through most of the circle | Motion capacity is probably not the dominant restriction | Check pierce timing, lead geometry, and process settings |
| Velocity remains below the command around the full circle | The contour is too small for the configured acceleration or path handling | Review controller motion settings and test a larger hole for comparison |
| Velocity collapses at lead-in entry or lead-out exit | Path transitions are concentrating heat locally | Shorten or reshape the transition without crossing the finished edge |
| Axes hesitate after piercing | Pierce energy continues entering one location | Remove avoidable delay between established arc and contour motion |
Use controller diagnostics, drive traces, or a timed motion record to compare commanded and actual velocity. Do not raise the programmed feed repeatedly when the axes cannot attain it; that changes the command without changing the heat exposure at the plate.
Is excess heat producing the dross?
Small-hole dross commonly develops because heat accumulates faster than the short contour can carry the torch away. The pierce heats the center region, the lead-in adds another heated path, and the circle returns rapidly to the entry area. A long lead-out or contour overlap reheats material that is already molten.
Map the deposit before changing settings. Heavy accumulation near the entry and exit points directs attention to pierce delay, lead geometry, and overlap. Dross distributed around the circumference directs attention to delivered speed, current, torch height, consumable condition, or gas performance. A localized flat or notch at closure points to the transition between the circle and lead-out.
The useful direction from the installation experience is faster piercing and cutting, because less residence time reduces heat buildup. Apply that direction through measured changes: minimize dead time after the pierce, maintain the highest stable contour speed allowed by the approved torch process, and avoid unnecessary lead-out heating. Faster is not a substitute for full penetration or a stable arc.
Should gas, current, or lead geometry change first?
Change one variable per coupon. Otherwise, a cleaner hole provides no evidence about which correction worked.
| Variable | Change it when | Watch for |
|---|---|---|
H17 gas setup |
The documented torch chart does not match the installed mixture, flow, pressure, or consumables | Arc stability, kerf ejection, edge condition, and consumable wear |
| Current | The selected consumable set and process chart call for another value | Incomplete penetration at too little delivered energy or wider heat input at too much |
| Feedrate | Actual motion can reach the revised command | Dross distribution, roundness, and full separation |
| Lead-in | Pierce damage intersects the finished circumference or entry heating is concentrated | Entry notch, uncut bridge, and molten material entering the finished edge |
| Lead-out | The exit reheats or crosses the completed contour | Closure divot, flat, or local dross deposit |
No exact amperage or feedrate follows from plate grade and dimensions alone. Select them from the Interlogic/Inova process data for the installed torch, consumables, gas combination, and thickness. The Burny 10 LCD must then deliver motion compatible with that process setting.
What procedure isolates and fixes the resolving branch?
- Record the installed torch consumables,
H17gas identification, current setting, programmed feedrate, pierce sequence, torch height settings, and lead geometry. - Inspect the orifice, electrode condition, alignment, gas delivery, work connection, and plate surface. Replace or correct any unstable physical element before cutting coupons.
- Confirm the consumable, gas, current, thickness, and speed combination against the torch process chart. Do not create an unverified hybrid recipe.
- Cut a baseline coupon and mark the program direction, entry point, and exit point. Photograph both faces and map where dross accumulates.
- Measure or trace actual axis velocity from pierce through contour closure. If motion hesitates or remains below command, correct that branch before changing gas.
- Reduce avoidable time between completed piercing and contour motion. Retest while holding gas, current, height, and geometry constant.
- Adjust the lead-in so the pierce remains away from the finished circumference and the transition enters cleanly. Remove a lead-out that crosses or reheats the completed edge.
- Increase cutting speed only within the documented process range and only when actual motion can follow it. Stop if penetration or arc stability degrades.
- Repeat the best setting across several holes on a fresh coupon. Measure diameter in more than one direction, inspect taper and entry damage, and compare top and bottom dross at the same locations.
FAQ
What happens if I increase programmed feed but dross does not change?
The axes may not be reaching the command on the 0.785 in circumference. Read actual contour velocity and inspect acceleration, entry, and exit behavior before raising the command again.
What happens if the lead-out crosses the start of the hole?
The arc reheats an already completed section and can leave a divot, flat, or local dross deposit. Shorten or remove the lead-out and inspect the closure point on the next coupon.
What happens if the pierce is too close to the finished edge?
Pierce damage and expelled metal can enter the final circumference. Move the entry path inward while keeping the transition short enough to limit heat accumulation.
What happens if I change the H17 mixture before checking motion?
A motion-limited hole may remain slow regardless of the gas change, and the test will mix two diagnostic branches. Confirm physical stability and actual velocity first, then compare gas configurations listed for the installed torch and consumables.
What happens if the hole looks round but measures undersize?
Visual roundness does not verify dimensional performance. Measure the final hole in multiple directions after cooling, inspect both faces for dross and taper, and accept the setting only after repeated holes meet the drawing requirement.