How to Achieve Stable Flatness for a Standalone XDFC250: 4 Core Steps — Inner Hole Alignment, Layered Cutting, Trial Cutting, and Sealing Surface Acceptance

The parameters of the hand-operated flange machine are not complicated, but rework of small flanges mostly occurs due to these issues: uncleaned inner holes, unaligned internal supports, full 0.2mm feed in one pass, and finishing turning without trial cutting. The XDFC250 has nominal specifications: flatness 0.10mm, roughness 3.2, cutting depth 0.2mm, applicable range 25–250mm, internal support positioning, and hand-operated speed 0–100r/min. To translate these nominal values into consistent performance for individual workpieces, we rely on a replicable first-piece working method instead of the subjective experience of veteran workers. This guide is written from the perspectives of team leader task arrangement and quality control archiving.

1. First Judge "Whether This Sealing Surface Is Worth Turning"

Three checks upon workpiece arrival:

• ‌Sealing surface type‌: Define tool paths separately for raised faces, flat faces, elliptical faces, serrated lines, shallow grooves, and valve seat faces. The XDFC250 supports end faces, elliptical faces and other forms, and is applicable to pump bodies, valve seats, compressors, and pipeline flanges. However, specific serrated lines, octagonal grooves, and deep/shallow grooves must match the corresponding sub-type tool post and accessories.

• ‌Damage depth‌: Handle light scratches, old gasket indentations, uniform corrosion, and local edge chipping differently. For severe local material shortage, base material cracks, and hardened heat-affected zones, evaluate repair welding or part replacement first, and do not blindly proceed with turning.

• ‌Inner hole condition‌: The internal support is centered by the hole wall. Rust, ellipse deformation, old sleeves, and coking in the inner hole will affect the rotation center. If the inner hole itself is out of tolerance, repair the inner hole first or switch to external clamping/special fixtures.

The hand-operated machine is suitable for "sealing surface restoration", not for "turning severely deformed parts into brand-new ones". When the damage exceeds the cutting capacity or affects the structural strength, outsource the processing or replace the flange.

2. Inner Hole Alignment: No Automatic Centering on Hand-Operated Machines, Ensure Accuracy Manually

• ‌Clean the inner hole‌: Use a wire brush to remove coke, and use solvent to eliminate old adhesive, ensuring no loose rust or hard caking. The contact area of the internal support legs must fit the full circumference of the hole wall tightly.

• ‌Select the internal support gear‌: Choose the support feet/centering range according to the actual inner hole diameter. The full 25–250mm working range does not rely on outer circle positioning. Internal support is more suitable for workpieces with polished outer walls, coatings, or incomplete removed insulation layers.

• ‌Equal load on three/multiple legs‌: Adjust the tightening force of each leg one by one to avoid force concentration on a single leg. For thin-walled stainless steel small flanges, reduce the jacking force according to the inner diameter and wall thickness to prevent deformation.

• ‌Idle runout verification‌: Do not install the tool, turn the hand crank at low speed for a full circle, and use a dial indicator to measure the flange surface/inner hole near the tool position. If the runout exceeds the acceptable value, readjust the internal support first before feeding.

• ‌Tool installation and centering‌: Adjust the tool tip height to the spindle rotation center. Replace the corresponding tool bar for deep and shallow grooves on the sealing surface. The feed of the hand-operated machine relies on a manual screw, so reset the feed scale to zero first.

3. Layered Cutting: 0.2mm Is the Upper Limit, Not the Feed per Pass

The XDFC250 has a nominal cutting depth of 0.2mm. On-site suggestions are classified by material:

• Carbon steel with light rust/old gasket indentation: First pass 0.10–0.15mm to peel off the hard skin, second pass 0.05–0.10mm for finishing turning. If the total allowance is small, you do not need to use the full 0.2mm.

• Stainless steel/hygienic grade material: The first pass should be smaller to avoid tool tip gnawing marks. The finishing turning focuses on improving Ra, not pursuing a large removal amount.

• Cast iron/old weld repair surface: Perform low-speed trial cutting on hard spots first, remove the hard skin in layers, and do not force a full 0.2mm cut in one pass.

• Serrated lines/shallow grooves: Divide into rough cutting and shaping according to the groove depth. The groove dimensions shall be subject to the drawings and forming tools, not estimated by hand operation.

• Hand-cranking rhythm: The nominal speed range is 0–100r/min. Use a low speed and shake the handle evenly for small-caliber finishing turning. The speed can be slightly higher for rough skins, as long as no vibration occurs and no long curled chips jam the tool.

4. First-Piece Trial Cutting and Record Sheet

For each new pipe diameter section, new base material, or new sealing surface form, process a first piece first, and do not directly perform finishing turning on the to-be-repaired workpiece:

• Clamp a waste flange/test block of the same material with internal support, and complete alignment and tool installation as described above.

• Perform a full circle of rough cutting, then measure flatness, depth, and runout.

• Perform a full circle of finish cutting, then measure Ra, flatness, sealing surface width/groove depth.

• Record: actual inner hole diameter, internal support gear, idle runout, first-pass/finishing allowance, rotation speed, measured flatness, measured Ra, and tool model.

• Proceed to the to-be-repaired workpieces only after the first piece is qualified. Parameters can be reused for the same batch and same caliber, but a new first-piece trial is required when changing the base material.

The hand-operated machine has no numerical control compensation. The first-piece process is to fix the relationship among "human operator, internal support, tool, and base material". Without trial cutting before finishing turning, the nominal flatness of 0.10mm may not be achieved on the actual workpiece.

(This article is compiled based on public enterprise data and industry information, for reference only. Specific product information and service terms are subject to the official release of the enterprise.)