In this guide 6 sections
A moulding plant needs machine and mould tracking, cycle time, shot counts and scrap by reason. An assembly plant needs a multi level bill of materials, kitting, station scans and shortage alerts. Plants that do both need the two models joined at the moulded part.
The unit of work is different
In moulding, the unit of work is a press running one mould on a shift. Output is counted in shots and good pieces. The plant lives or dies on cycle time.
In assembly, the unit of work is a finished cooker or mixer built from many parts. Output depends on whether every part reached the station, in the right quantity, at the right time.
Software that fits one will feel clumsy in the other. A mould tracker has no use for a kit list. A kit list has no place for a cooling time.
What a moulding plant needs
Start with the machine and mould master. Each injection press has a tonnage and a shot size, and each mould has cavities, a life count and a maintenance history. The plan must match them before a job is released.
Then track the run. Record the cycle time against the standard, the shots made, the good pieces and the rejects by reason, such as flash, short shot, sink mark or black spots. Regrind use and colour changeover time belong here too.
Resin and masterbatch lots matter for traceability. A bucket that cracks in a dealer’s store should lead you back to a resin lot and a press. Trace it in minutes.
- Machine tonnage and shot size
- Mould cavities and shot count since service
- Cycle time against standard
- Reject reason codes
- Resin, regrind and masterbatch ratio
What an assembly plant needs
Assembly starts with the bill of materials. A cooker or mixer has sub assemblies, bought out parts and moulded housings, and the bill must show each level with its quantity and revision.
From the bill comes kitting. The store issues a kit to the line, and a shortage shows before the shift, not at the station. Station scans then record who built what and when, which feeds serial tracking and warranty.
Engineering changes hit assembly hard. When a rocker switch is replaced mid month, the system must show which kits use the old part and which the new.
- Multi level bill of materials with revisions
- Kit issue and shortage list
- Station scans and serial numbers
- Rework and repair loop
- Bought out part inspection
Where the two meet
Many household plants do both. They mould the jar, lid and housing, then assemble the product around a bought motor. The moulded part is the link between the two.
The moulding output must feed the assembly stock with its lot and colour. If the lid is short, the planner should see it as a moulding job that needs a slot, not as a mystery on the assembly board.
Check how a vendor handles this. A system built only for assembly often treats moulded parts as purchased items, which hides cycle time and scrap behind a single price.
How to choose between them
Write down which of your problems are about presses and which are about missing parts. Late jobs from mould changeovers point to moulding features, while idle lines from missing lids or switches point to kitting and bill control.
In a demo, have the vendor run a mould reaching its service count and a bill revision hitting open kits. A good system handles one of these well and the other adequately, and a plant that does both needs both.
Pick your three worst weeks from last quarter. Note which feature would have prevented each. That list is your requirement.
Moulding and assembly feature comparison sheet
A sheet with two columns, moulding and assembly, and twelve rows of features. Rows include mould shot count, cycle time, reject reason codes, multi level bill, kitting, shortage list and station scans. Each row has a must have, nice to have or not needed tick, plus a note field.
Open a blank worksheet to printQuestions owners ask
Can one system handle both moulding and assembly?
Yes, if it models machines and moulds as well as multi level bills. Check that moulded parts keep their cycle time and scrap data and do not become plain purchased items.
Why does mould tracking matter so much?
A worn mould makes flash and short shots, and a missed service date can stop a high volume part. Shot counts against service limits let you plan maintenance before quality drops.
What is kitting and why do assemblers use it?
Kitting means issuing all parts for a batch to the line together. Shortages are found in the store before the shift starts, so the line does not stop mid batch.
Do we need real time machine data from presses?
Not at the start. Operators entering shots and rejects each hour is often enough. Add machine signals later if the manual figures prove too slow or too inaccurate.