Robotic Part Removal and Automatic Cavity Separation
A core strength of RKT’s injection molding operation is automated robotic part removal with integrated cavity separation. Molded parts are removed directly from the machine and systematically sorted into designated containers, most often collapsible small load carriers (KLTs) or, when required, custom-designed trays.
Robotic cavity-separated part handling is standard practice across nearly all customer projects. This high level of automation delivers measurable benefits in process reliability and product quality. Separating parts by cavity ensures cavity level traceability, enhances quality control, prevents part mixing, and provides optimal traceability throughout the entire production process.
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More InformationThe advantages:
- Minimized Damage: Parts are placed, not dropped into containers, preventing damage and contamination.
- Integrated Quality Control: Controlled removal and segregation of QC parts, sprues, and initial parts at start-up
- Cavity-Level Traceability: Segregated sorting ensures each part can be traced to its specific cavity, enabling fast defect analysis and effective quality control.
- Controlled removal and disposal of defective parts
- Reduced Scrap Costs: Separation of conforming and non-conforming parts reduces waste, optimizing material usage.
- Precise, Accurate Production Tracking: Automated part handling provides reliable delivery quantities and streamlined logistics.
Robotic part removal to prevent damage
At RKT, we rely on monitored robotic part removal using 5‑axis, 6‑axis, or linear handling systems to ensure the highest part quality and process reliability. While allowing molded parts to simply drop into collection bins may appear efficient, freshly molded components are still warm and can easily be damaged, deformed, or contaminated. In addition, a single non-demolded part of a multi-cavity mold leads to filling imbalances, over-injection, and poor quality of the remaining parts.
Our controlled robotic handling eliminates these risks. Using advanced vacuum gripper technology, each molded part is gently removed, inspected, and placed in a defined location. This ensures that no component remains in the mold, sprues are safely removed, and critical process functions, such as TGS and QC part separation, are automated at specified intervals.
During start-up or after maintenance interruptions, when material degradation may occur in screws or hot runners, the robot selectively sorts out suspect parts molded from degraded resin, automatically routing them to scrap. This level of process automation ensures that only conforming parts continue downstream.
Cavity segregation for consistent product quality
The integrity of the components is one key argument for robotic part removal; the other is the ability to sort parts by cavity. For example, with a four-cavity mold, all parts from the first cavity or nest are collected in Box 1, parts from the second cavity in Box 2, and so on. Several small containers from the different nests with defined quantities then make up the final container that is delivered to the customer. During removal, the number of parts is counted, so the delivery quantity is precisely traceable. Thanks to this counting, no scheduled maintenance can be missed either, as the machine prompts for maintenance after a defined number of shots. If maintenance is not performed, the machine will stop until it has been completed.
Separating the parts becomes especially important when a defect occurs. With high-cavity molds designed for high part volumes, stable, uninterrupted production is essential. If one cavity is damaged, causing the respective plastic part to be molded with defects, only the parts in that particular nest are affected and are directly sorted out as scrap into a container through nest segregation. All other containers hold the good parts from the remaining cavities and can be shipped. No sorting is required. Furthermore, in this case – with a damaged cavity in the mold – production can continue if certain delivery quantities and deadlines must be met; only the affected nest is sorted out, and the repair can then be carried out when it fits within the production schedule. In contrast, if a defect is detected during production without cavity-separated sorting, all parts produced in that batch must be sorted or discarded entirely, and production must be halted to find and eliminate the defect.
In addition to robotic part removal, we also use a linear handling system for part removal in our production with high-cavity 128-cavity molds, for example, which operates in a similar manner. The parts are likewise removed in a controlled, vacuum-based process, and TGS parts, QC parts, sprues, and start-up parts are separated. The good parts removed by this handling system are collected directly as bulk material in a good-parts box. Traceability is ensured here through the first-in, first-out principle. Moreover, this linear handling system makes it possible, when a specific cavity has a defect, to separately dispose of that part during removal
Added value for medical technology and life sciences
This controlled part removal and intelligent sorting strategy supports the stringent requirements of the medical device and life science industries, where process consistency, cleanliness, and traceability are non‑negotiable. The result is a stable, reproducible process that drastically reduces scrap rates and quality costs.
Robotic handling may slightly extend cycle times (typically by 1.0 to 1.5 seconds), however, the long‑term quality and productivity advantages of reduced damage, guaranteed traceability, and uninterrupted production far outweigh the marginal increase. For this reason, RKT employs robotic part removal and nest segregation across nearly all production lines.
