Powder Coating

Powder coating is an electrostatic surface treatment process where dry powder is applied to a metal part and then cured in an oven to form a hard, uniform protective layer. It produces a more durable and scratch-resistant finish than liquid paint, with no solvent emissions.

See Threading and Finishing for the full surface treatment workflow.

When to Use Powder Coating

Use powder coating when:

• A durable, scratch-resistant finish is required
• Uniform colour coverage is needed across complex geometries
• The part will be used outdoors or in corrosive environments
• An environmentally friendly process is preferred (no solvents, overspray can be recycled)

Step-by-step

1. Select the node before or after which the coating should be applied, in the Tree View or Graph View.
2. Right-click the node and choose Append node(s) (or Prepend node(s)) from the context menu.
3. In the process selector dialog, choose Powder Coating.
4. If prompted, select the coating colour and review the film thickness — for most coating types this dialog opens automatically right after the node is created. Three types — Cathodic dip painting, Electro galvanizing, and Hot dip galvanizing — auto-populate with no dialog at all.

Result

After running Powder Coating:

• A Transform node appears in the Graph View at the position where it was inserted
• The Tree View shows the coating parameters and any warnings
• Export data includes specifications for the powder coating process

Other Surface Treatment Methods

WSi supports multiple surface treatment methods:

• Spray Painting — liquid paint for colour/RAL finishes, complex geometries, or thin coats
• Countersinking — conical recesses for flush-fit fasteners
• Tapping — internal threads in sheet metal or tube

See Threading and Finishing for the full overview.

WARNING

Coating processes are optional modules. If the coating module is not licensed, Powder Coating is blocked. Contact your sales representative at WSoptics to obtain the relevant licence.

Parameters

The parameters for this process are configured in the database — see the Coating page.

Technical Background

Powder coating is an electrostatic dry coating process. The powder — a mixture of finely ground polymer resin, pigment, and additives — is applied to the part using a spray gun that imparts a electrostatic charge (typically 20–100 kV DC) on the powder particles. The part is grounded, so the charged particles are attracted to its surface and cling evenly across flat surfaces, edges, and recesses.

After application, the part is placed in a curing oven (typically 160–200°C for thermosetting powders, or lower for UV-cure systems). Under heat, the powder melts, flows out into a uniform film, and then chemically cross-links ( thermosets) or hardens (thermoplastics) to form a continuous, durable coating. The result is a uniform thickness coating with no sags, runs, or solvent marks.

Thermoplastic powders (nylon, PVC) fuse on cooling and can be re-melted; thermosetting powders (epoxy, polyester, epoxy-polyester hybrid) undergo an irreversible chemical reaction and cannot be re-melted once cured. The coating thickness is typically 60–120 µm for functional coatings; decorative coatings may be thinner.

Pretreatment is critical to coating adhesion and corrosion resistance. The part surface is cleaned (degreased), then given a chemical conversion coating — commonly iron phosphate or zinc phosphate for steel, or chromic acid or chrome-free for aluminium. This layer improves adhesion and provides a degree of corrosion resistance on its own, with the powder coating as the outer barrier.