Excel vs ERP for plastics manufacturing: where the moulding shop sheets stop coping

Few moulding plants chose spreadsheets on purpose. The planner made a machine loading sheet, stores kept a resin stock file, the shift supervisor filled a register, and quality had a rejection sheet. Over a few years the plant came to run on four or five files, each understood fully by the person who made it.

That is not a failure. Excel is flexible, everyone can use it, and it costs nothing extra. The real question is when the plant's needs go past what a handful of separate files can reliably hold.

Where Excel works well in a moulding plant

• Quotations: part weight, runner weight, cycle time, cavities and machine rate in one model that one person maintains.
• One-off studies, such as comparing cycle times before and after a mould repair, or a scrap Pareto for one part.
• A small plant with a few machines running long jobs, where moulds change once or twice a week.
• Charts and summaries drawn from figures already held in another system.

Where do spreadsheets become difficult?

The machine loading sheet is out of date by mid-shift

The loading sheet shows which mould is on which machine and what follows. A breakdown, a rush order or a mould sent for repair changes it, and the floor works to whichever printout it has. The more machines and the more mould changes, the faster the sheet falls behind.

Counts arrive after the shift

The counter reading goes into a register at the end of the shift and into the sheet the next morning. By then the machine that ran slow all night has already lost the output, and the totals do not say whether it was the cycle time, a blocked cavity or a stop.

Resin, masterbatch and regrind by lot

A stock file can show how many bags of a grade are in stores. It struggles to show which lot went to which job, how much regrind went back into the hopper, and what is allocated to jobs not yet started. Shortages are usually found when the hopper is nearly empty.

Scrap and downtime with no reason attached

A rejection sheet with a total per day does not show short shots against flash, or the mould and shift they came from. Downtime written as "breakdown" does not separate a heater band from a water leak from waiting for the setter. Without the reason, the fix is a guess.

Traceability for a complaint

A customer reports brittle parts or a shade mismatch from one delivery. Answering means matching the delivery to the moulding date, the machine, the shift and the resin and masterbatch lots, from a dispatch register, the shift register and stores slips. It can be done, but it takes hours, and a gap in any one file breaks the chain.

Parts at the vendor

Parts sent for printing or plating are tracked in a challan book or a separate sheet. Whether everything came back, and how many were rejected by the vendor, is often found out at packing.

Reporting across files

Output against target per machine, scrap by mould and cost per order each need data from three or four sheets. They are built at month end, by hand, and they are old by the time anyone reads them.

Spreadsheets and ERP compared, task by task

An ERP is an operational system, not a bigger spreadsheet

The difference is when the data is made. The loading sheet and the register are written up once the shift is over. A manufacturing ERP with shop-floor recording is filled in as the work happens: stores issues a resin lot to the job, the operator logs the counter reading and the rejects at the machine, QC approves the first-off before the run counts. Reports are read from those entries, not put together.

This is why replacing Excel with an ERP that only covers purchase, stock and invoices often disappoints a moulder. The sheets that cause the most trouble are the loading sheet and the shift register, and an ERP without machine-level recording leaves both in place.

When should a plastics manufacturer move from Excel to ERP?

There is no machine count at which spreadsheets must go. A better test is how often the loading sheet, resin file and register fail to tell you, right now, what is happening. These are the triggers moulding plants most often describe.

• Several people edit the plan. The planner, the shift supervisor and stores each keep their own version of what runs next.
• Many machines run at once. One person can follow five machines in a sheet; with twenty running three shifts, nobody has the whole picture.
• Moulds change often. Daily mould changes, short runs and new parts make the loading sheet a full-time job.
• Resin and masterbatch are hard to follow. Stock in the file is not in stores, or a job stops because the masterbatch was used on another one.
• Production updates arrive late. Counts reach the office the next morning, so a slow machine is found a shift too late.
• QC records are on paper. First-off approvals and in-process checks sit in a register that is not linked to the batch.
• A trace takes more than an hour. Linking a delivery to its resin lot means opening several registers and files.
• Rejects and rework are invisible. Nobody can say how many parts were reworked or degated by hand last week, or on which mould.
• Customer requirements are growing. A new customer asks for resin lot traceability, inspection records or delivery performance you cannot produce quickly.
• Current WIP is unknown. Finding out how many moulded parts are waiting for printing, assembly or a vendor return needs a walk round the floor.

None of these means Excel has failed. They mean the plant has outgrown separate files. When two or three of them show up together, the planner and stores are usually spending more hours on the files than a system would take. The guide to implementing ERP in a plastics plant covers what the move involves.

Keeping what works

The quotation sheet, cycle time studies and one-off analysis can stay in Excel, fed by exports from the system. What moves is the operational record: jobs on machines, material by lot, counts, scrap, inspections and dispatch. In FleekERP that record sits on the work order, with production control showing each machine against its target and inventory and lot traceability on the same lots, while the books stay in Tally or Zoho.

For how machines, moulds and resin lots run on one record, see FleekERP for plastics and moulding plants.