Cutting off plastic sprues
Laser cutting is an innovative, non-contact process for removing sprues from plastic parts directly after injection moulding.
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:
- Camera-supported component recognition
- Automatic focussing
- Dynamic cutting according to component contour
- Integrated special laser fume extraction
Get advice now
Benefit from our experience in laser material processing. Our experts will support you in selecting the right technology for your application.
Suitable products
FM Cardmaker
From manual machine to automatic labelling machine. With the Cardmaker function module, nameplates can also be automatically labelled with consecutive numbers or variable data
Laser workstation LG 200
Modularity as a pioneering concept
PenSoft Control
Easy-to-use interface for laser applications
Laser system with conveyor belt
Automatic laser system with flexible workpiece carriers
Smartlaser LG20
The intuitive system for professional results
Desktop Laser LG50
Simple, compact and reliable
Desktop Laser LG100
Premium table system in industrial laser technology
Desktop Laser LG150
The all-rounder in industrial laser technology
Rotary table laser LG200 RT
For maximum production speed
Laser workstation LG300
Spacious work area and double pull-out table for maximum throughput rates
LG300 RT round table laser system
Maximum productivity in large format
Laser workstation LG 500
the top class for XL formats in laser processing
SG200 Weld
Dynamic Precision Welding: Developed for reliable welding of the smallest components with state-of-the-art software and camera technology.
OEM fibreline
Ready-to-install laser for numerous applications
OEM Carbonline
CO₂ technology for versatile applications
LG500 A Double shutter
Automatic loading system for large workpieces
LG200 RT with vibratory feeder
based on LG200 RT rotary table laser system for automatic labelling of bulk goods
Laser workstation LG 500 Robo
Fully automatic and flexible with integrated robot
Rotary transfer laser system
Automatic with flexible workpiece holders
Integration station
Laser system for easy integration into conveyors
Further applications
Technical films
Precision at the speed of light - laser cutting of foils with Galvo technology
Perforating and punching
Our systems for laser marking of type plates offer the largest selection of different solutions for every application on the market.
Laser labels - Laser foils
Flexible, tamper-proof and permanent labelling
Industries
Mechanical engineering
We use state-of-the-art laser technology to create precise, durable solutions for demanding plant and mechanical engineering applications
Tool+mould making
Our laser machines enable precise engraving and labelling in tool and mould making, which increases efficiency and adaptation to workpiece geometries
Electronics industry
Penteq laser machines offer precise cutting, welding and marking for the electrical industry, ideal for battery cells and electronic components
Automotive industry
Penteq laser machines enable precise cutting, welding and labelling in the automotive industry, especially for batteries and metal components
Tool manufacturer
Penteq laser systems enable precise, efficient and cost-saving production of durable tools - innovative and robust
Air+Space
With innovative laser technology, Penteq delivers precise and reliable solutions for the highest demands in the aerospace industry
Maritime industry
Penteq supplies robust laser technology for precise material processing and labelling despite the harshest maritime environments