Kitchenware and hotel equipment covers two problems that look similar and are not. Flat products — sinks, worktops, splashbacks, serving counters — are finished as sheet and judged on flatness and pattern consistency. Formed products — pots, pans, bowls, chafing dishes, urns — are finished after drawing or spinning, and judged on how the finish survives a curved, work-hardened surface.
Most suppliers of this sector need both, often on the same site, and the finishing line has to be chosen for the mix rather than for either product alone.
Two different starting points
A flat sink or worktop starts as sheet and can be finished before forming or after. Finishing before forming gives a more consistent pattern and a faster line, but the forming operation then has to be gentle enough not to mark the surface. Finishing after forming protects the finish through the press but is slower and requires handling that suits a three-dimensional part.
A drawn pot or spun bowl starts as a blank that has already been work-hardened and has a surface that is no longer uniform. The finishing sequence has to remove the drawing marks first, which means more grinding stock removal than a flat product needs, and it has to do so without cutting through the wall thickness at the rim or the base radius.
Finishes typically specified
- 8K super mirror — cookware and serving pieces where reflectivity is the selling point. On formed parts the challenge is not achieving the mirror but keeping it uniform across a curvature, where the polishing head sees a constantly changing contact angle.
- No.4 — commercial sinks, worktops and preparation tables. No.4 is the practical default for a working kitchen: it hides scratches, tolerates daily cleaning, and does not show every fingerprint the way a mirror does.
- Hairline (HL) — front-of-house equipment and hotel service pieces where a finer, more decorative satin is wanted.
- Vibration (SB) — non-directional satin for parts that will be formed after finishing, and for mixed-orientation assemblies where a directional grain would clash.
Coil line or sheet line
Volume cookware and stamped components are usually made from pre-finished coil: the coil is polished, then blanks are stamped and formed. This is the cheapest route per piece at volume, and it is the reason coil lines dominate the kitchenware belt in Foshan and Guangdong generally.
Heavy-gauge sinks, worktops and custom hotel equipment are usually finished as sheet, either before or after fabrication. Sheet lines handle the thickness and the size that coil lines cannot, and they allow a fabricator to finish a welded assembly as a single piece so the weld dressing and the surrounding finish match.
Process sequence
A typical sequence for formed parts runs coarse grinding to remove drawing marks, intermediate grinding to remove the coarse scratches, polishing to bring up the reflectivity, buffing with compound for the final gloss, and then a cleaning stage to remove compound residue. The cleaning stage is the one most often under-specified and the one that causes the most customer complaints, because compound left in a rim or a handle joint shows up weeks later.
For flat products the sequence is shorter: grinding to establish the pattern, polishing if a higher reflectivity is required, and passivation or cleaning before packing. The pattern is established in the first head, and every later head only refines it — which is why a worn first belt shows up as a pattern defect on the whole batch.
What goes wrong, and why
- Orange peel on drawn parts — the surface has been polished but the underlying deformation from drawing was never fully removed. More polishing does not fix it, more stock removal at the grinding stage does.
- Polishing marks that follow the curvature — the head pressure and the contact angle change across a curved part. Uniform results on curved work depend on controlled pressure, not on operator technique.
- Compound residue in joints and rims — an under-specified cleaning stage. It is invisible at dispatch and obvious after the first wash in service.
- Pattern mismatch between a formed body and a flat lid — the two were finished on different lines or in different orientations. On a matched set this is immediately visible.
- Scratches from nesting — stacked pans rubbing in transit. Interleaving or film is cheaper than rework.
Oil-type or dry grinding
Oil-type grinding is common in this sector because it controls dust and gives a cooler cut on thin material, which matters on cookware where heat distortion shows immediately. The trade-off is that the oil has to be removed completely before any buffing compound is applied, and the cleaning stage has to be designed for it rather than added at the end.
Dry grinding is simpler to clean up after and is often preferred for flat sheet work. The choice is usually made on the product mix and the site conditions rather than on the finish quality, because both routes can produce the same pattern when the abrasive sequence is correct.
Recommended machines
- Coil polishing lines for pre-finished cookware blanks
- Sheet polishing machines for sinks, worktops and fabricated assemblies
- Hairline and SB polishing machines for decorative service pieces
- 8K mirror lines for sheet for mirror cookware and serving ware