Laser, mechanical engraving or CNC milling? Choose by the required result

Start with the required result, not the machine name

You may need a serial number on a metal component, a permanent label on a control panel, a precise contour cut from sheet material or a deep relief in MDF. All of these jobs may be described as “engraving”, yet they require different manufacturing processes.

First define what must actually be created on the product:

• a high-contrast mark without tactile depth;
• a shallow or deeper recess;
• removal of paint or another surface layer;
• a mechanically engraved groove with colour fill;
• a cut-out, pocket, profile or three-dimensional relief;
• identical marking across a batch or variable data on every part.

Only then does it make sense to choose between laser processing, mechanical engraving and CNC milling. The processes overlap, but they do not automatically provide the same appearance, depth or durability.

Marking is not the same as engraving

Laser marking covers several processes. The beam can change the colour of a surface, remove a thin coating or remove part of the base material. Only the last of these creates a recessed laser engraving. Its achievable depth depends on the material, source, filled area and number of passes, not merely on machine power.

Mechanical engraving uses a tool. A diamond point can scribe or displace the surface, while a rotating cutter removes material. CNC milling applies controlled machining more broadly and can produce pockets, cut-outs, profiles and 2D or 3D shapes as well as fine motifs.

As a practical starting point:

• choose laser for fine 2D marks, logos, numbers or codes;
• choose mechanical engraving for a tactile line, a traditional finish or a groove intended for colour filling;
• choose CNC milling for the shape of the part, substantial material removal, deep relief or large formats.

The final choice must still reflect the material, finish, part geometry and required inspection method.

Laser: contactless marking, engraving and cutting

A laser concentrates energy on the material without a cutting tool touching the part. This suits fine graphics, small text and repeatable motifs. Contactless processing does not eliminate the need for fixturing: every component must be located consistently and the working surface must remain in focus.

Tiskárna Jelínek operates two laser technologies:

• a 40 W Epilog CO₂ laser for cutting and engraving selected non-metallic materials such as wood, plywood, acrylic, paper, selected textiles, leather, glass and stamp rubber;
• a 50 W fibre laser for fine marking of metal parts, with 110 × 110 and up to 300 × 300 mm optics and a rotary attachment for selected cylindrical profiles.

For metals, it is important to distinguish a contrast change, coating removal and engraving into the base material. In our production we specify deep engraving for materials such as aluminium and brass, while stainless steel is used primarily for marking. The result must be confirmed on the actual alloy and surface.

Laser processing can also suit repeated batches and variable data. Cycle time, however, depends on motif size and fill, required depth, number of passes, loading, fixturing and readability checks—not just beam speed.

Mechanical engraving: a tactile mark with optional colour fill

Mechanical engraving creates the mark through physical contact with a tool. Diamond drag engraving can produce a fine bright line on a suitable metal or other hard surface. A rotating cutter removes material and allows groove width and depth to be controlled through the selected tool and process.

The result is usually more tactile than a simple laser-induced colour change. A groove in a single-colour material may not provide strong visual contrast by itself, so it can be colour filled where appropriate. The durability of that fill must be assessed separately from the durability of the engraved recess.

For smaller formats we use a Venture engraver with a 600 × 400 mm working area. The choice between a diamond point and a rotating cutter depends on the material, required appearance and depth. For a metal plate, control panel or presentation item, we therefore need to know whether the motif must only be visible, tactile or subsequently colour filled.

CNC milling: when the shape of the product changes

When a job requires a pocket, deeper relief, cut-out, finished contour or three-dimensional shape, CNC milling becomes the main option. A rotating tool removes material along a programmed path and can work at several depth levels. Unlike surface marking, the process often creates the geometry of the product itself.

Our large-format COMAGRAV router has a usable area of approximately 2 × 3 m and processes both 2D and 3D data. Typical materials include extruded polystyrene, MDF, foamed PVC, aluminium composite panels, aluminium and brass. Outputs range from technical plates and shaped signs to dimensional lettering, deep decorative motifs and 3D logos or architectural elements.

Secure workholding, tool access, internal corner radii, material thickness and flatness are critical. Detail is limited by tool diameter and geometry, so a deep narrow groove may require a different design from the same motif produced as a laser mark.

Material alone is not enough: finish, composition and geometry matter

“Plastic” or “metal” is too general for selecting a process. For metals we need the alloy and surface finish: bare, anodised, painted and powder-coated parts behave differently. With plastics, the exact polymer, pigment, reinforcement and additives can all affect the result.

Precise material identification is also a laser-safety requirement. Materials such as PVC and some plastics containing problematic additives or halogens must not be laser processed because of hazardous emissions and potential machine damage. A material unsuitable for laser may be machinable under suitable conditions, although chips, dust, cooling and extraction still have to be managed.

Geometry matters just as much. A laser needs access and correct focus; a rotary attachment may help with cylindrical items. A mechanical tool requires clearance and secure clamping. For large or complex parts, a drawing, 3D model and physical sample are more useful than photographs alone.

Accuracy, durability and cost cannot be reduced to one parameter

Laser resolution, machine positioning accuracy and finished-part tolerance are different values. Fixturing, datum choice, focus, surface condition, heat, the tool, clamping and measurement method all affect the result. We therefore do not promise a universal tolerance or minimum text size without assessing the actual part.

Durability cannot be inferred from the process name either. A deeper motif will not disappear with light surface wear, but readability may still be affected by corrosion, chemical cleaning, subsequent finishing or loss of colour fill. For industrial codes, the requirement may go beyond successful scanning and include a defined verification method.

Batch economics include data preparation, fixture production, loading operations, toolpath or hatch area, depth, tool changes and inspection. Laser is often efficient for fine 2D identification and variable data, but multi-pass deep engraving increases cycle time. CNC and mechanical engraving require tools and firm workholding, yet can create a groove, hole and final contour in one program.

Combining processes is often the best solution

The decision need not be simply “laser or milling”. Some projects benefit from a combined route:

• mill the contour, holes and pockets, then add fine numbers or a code by laser;
• machine dimensional lettering and subsequently finish or mark its surface;
• mechanically engrave a deeper groove and fill it with a contrasting colour;
• cut a detailed non-metal sheet component with a CO₂ laser and mark its metal counterpart with a fibre laser.

Combining technologies adds production steps, but it can meet geometry, appearance and readability requirements better than forcing one process to do everything. It makes sense when the required result matters more than a formal preference for a single machine.

What to send for technical assessment and quotation

For a faster recommendation, provide:

• a photograph of the complete product and a close-up of the processing area;
• a dimensioned drawing showing motif position and genuinely functional tolerances;
• ideally a 3D model for a three-dimensional part;
• exact material, alloy and finish identification, and a safety data sheet where relevant;
• vector artwork and a description of variable data;
• required appearance, contrast, depth and any colour fill;
• use, cleaning method and expected mechanical or chemical exposure;
• quantity in the first batch and expected repeat batches;
• any sample, measurement or code-verification requirement.

If some information is unavailable, send a physical sample and describe the part’s function. Because Tiskárna Jelínek operates CO₂ and fibre lasers, mechanical engraving and large-format CNC milling, we can compare several realistic production routes and recommend the process according to the required outcome rather than one available technology.