Excessive accumulation of work-in-process (WIP) and semi-finished goods occupies valuable workshop space and ties up working capital; it also increases the risk of material damage, mix-ups, and spoilage due to aging, while masking underlying issues such as unbalanced production scheduling and poor process coordination. By optimizing scheduling rules, process coordination, inventory standards, and shop-floor management, it is possible to progressively reduce semi-finished goods inventory and improve material turnover efficiency.
Injection molding production is scheduled based on the daily consumption requirements of downstream assembly and outsourced processes; rather than producing the entire order volume in a single large batch, a phased production approach is adopted.
Establish a maximum inventory warning level for semi-finished goods and set a safety ceiling for each product; temporarily halt production when stock reaches this threshold to prevent accumulation caused by continued output.
Reduce instances of early production; do not schedule production ahead of time for products without tight delivery deadlines; and minimize the likelihood of long-term storage of semi-finished goods.
The injection molding process and subsequent processes such as assembly, packaging, and spraying simultaneously share production capacity information. When the production capacity in the latter stages is insufficient, the injection molding output speed will be slowed down in a timely manner.
For semi-finished products requiring outsourced processing, confirm the schedule for outsourced goods receipt in advance to prevent situations where large quantities of completed semi-finished products cannot be transported in a timely manner.
In the event of downstream equipment failure or personnel shortages, injection molding production schedules must be adjusted immediately; otherwise, continued production will rapidly lead to a backlog of inventory.
Prioritize the production of orders with short lead times that can be immediately processed in downstream stages; for products with a high risk associated with long-term storage, schedule production as close to the shipment date as possible.
Small-batch orders are consolidated for production and prioritized for outbound shipment upon completion, preventing the simultaneous accumulation of various semi-finished products on the workshop floor.
Effectively control the frequency of machine mold changes to minimize frequent product switching, which leads to the simultaneous production and concurrent accumulation of multiple types of semi-finished goods.
Designate specific storage areas for semi-finished products and implement organized storage management; clearly label item names, batch numbers, quantities, and production dates to prevent the mixing of stock and ensure that older batches are used first.
Adhere to the First-In, First-Out (FIFO) principle by prioritizing the transfer of semi-finished products manufactured earlier, thereby preventing quality issues-such as deformation, yellowing, or dust contamination-associated with prolonged storage.
Control the volume of temporary inventory around the machine; keep only semi-finished goods that can be moved within a short time next to the machine, and promptly transfer excess materials to designated areas.
If batches of defective items are not sorted and disposed of in a timely manner, they may become mixed with qualified semi-finished products, resulting in dead stock.
The machine performs first-piece confirmation and process inspection to reduce defective output;
Designate a separate area for defective semi-finished products and schedule regular rework or crushing for recycling to prevent long-term stockpiling.
Reduce intermittent defects caused by process fluctuations and prevent the accumulation of large quantities of semi-finished goods that cannot move to the next stage due to undetermined quality status.
Periodically track the inventory turnover days for various types of semi-finished goods, paying particular attention to stagnant items that have remained idle for extended periods:
Analyze the causes of slow-moving inventory: overproduction, changes in customer demand, quality disputes, and suspension of downstream processes.
Differentiated disposition plans: coordinate customer pickup, arrange for rework, and evaluate options for recycling or crushing to prevent the continued tie-up of space and capital.
Dynamically adjust safety stock standards for various product categories based on historical turnover data.
Incorporate semi-finished goods inventory turnover into production planning and performance metrics for team leaders to avoid a singular focus on machine cycle output while neglecting downstream consumption capacity. Encourage the shop floor to adopt a production mindset of "matching output to consumption," rather than setting warehouse stockpiling as the target for production capacity.
With a rational production schedule, seamless information exchange between upstream and downstream processes, and standardized material flow, the inventory levels of semi-finished goods and work-in-progress within the workshop can be effectively controlled; this helps alleviate capital tie-up and space constraints while mitigating the risk of material quality degradation.
