Cutting off plastic sprues

Laser cutting is an innovative, non-contact process for removing sprues from plastic parts directly after injection moulding.

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Cutting off plastic sprues

Precise. Contactless. Efficient.

The sprue is the area of a plastic part through which the melt enters the mould during the injection moulding process. After solidification, this connecting web is separated. It can vary depending on the size and geometry of the moulded part and the injection process (spot, film or cold runner gate).

What is laser cutting of plastic sprues?

Laser cutting is an innovative, non-contact process for removing sprues from plastic parts directly after injection moulding. Using high-precision laser technology, the sprues are removed cleanly and in a material-saving manner - without mechanical stress on the workpiece.

Why laser technology instead of mechanical separation?

Conventional methods such as punching or cutting reach their limits with complex geometries or sensitive materials. Laser-based systems offer decisive advantages here:

Non-contact: No tool wear, no mechanical deformation
Maximum precision: Ideal for intricate structures and tight tolerances
Clean cutting edges: Hardly any reworking necessary
Can be automated: Can be integrated into existing production lines

Typical areas of application

Laser cutting is particularly suitable for:

Medical technology - sterile processing without residues
Automotive industry - high repeat accuracy for series production
Electronic components - finest details without microcracks
Consumer goods industry - clean surfaces without burrs

Automation & inline capability

A major advantage is that laser cutting can be easily integrated into automated production lines - inline directly after injection moulding or in separate post-processing cells.

Robot-assisted feeding
Cycle time-optimised processing
Interfaces to MES/ERP systems

Comparison of sprue cutting processes

Criterion	Laser cutting	Mechanical (knife/punch)	Thermal (hot cutter)	Manual (pliers, knife)
Non-contact	✔️ Yes	❌ No	❌ No	❌ No
Cutting quality	⭐⭐⭐⭐ Very high	⭐⭐ Medium	⭐ Low	⭐ Low
Burr formation	❌ None or minimal	✔️ Possible	✔️ Clear	✔️ Clear
Material deformation	❌ None	✔️ Possible (especially for thin parts)	✔️ High (heat distortion)	✔️ Possible
Repeatability	⭐⭐⭐⭐ High	⭐⭐ Medium	⭐ Low	❌ None
Automation capability	✔️ Very good	✔️ Possible, but limited	❌ Difficult	❌ Not possible
Cutting speed	⭐⭐⭐ Fast	⭐⭐⭐⭐ Very fast	⭐⭐ Medium	⭐ Slowly
Tool wear	❌ None	✔️ High (cutting, punching)	✔️ High (heating elements)	✔️ High
Costs per part (long-term)	⭐⭐ Medium	⭐⭐ Medium	⭐ Low short-term, high long-term	Low for small series
Investment costs	🡹 High (system, laser source)	🡹 Means (tools + mechanics)	🡻 Low	🡻 Very low
Flexibility with geometries	⭐⭐⭐⭐ Very high (also 3D)	⭐⭐ Medium (depending on mould shape)	⭐ Low	⭐⭐ Medium
Post-processing necessary?	❌ Mostly not	✔️ Frequent	✔️ Yes	✔️ Yes
Suitable for series production	✔️ Optimal	✔️ Restricted	❌ No	❌ No

Frequently asked questions (FAQ)

Which materials can be cut with a laser?

All common thermoplastics such as ABS, PC, PP, PE, POM and fibre-reinforced plastics.

How fast is the process?

Depending on component geometry and material: a few seconds per interface - ideal for short cycle times in mass production.

Is post-processing necessary?

Not in most cases. The edges are smooth and clean, without mechanical damage.

Our laser technology in detail

We use modern CO₂, fibre or UV lasers - depending on the requirements and the material to be separated. Our lasers can be optionally equipped with vision systems and offer: