Metal processing workflow: from coil to dispatch

The stages below follow one typical job: a cold rolled steel coil, 1250 mm wide and 1.6 mm thick, slit into six narrow coils for a tube maker, with part of the order cut to length into sheets for another customer. A plate cutting shop or a heat treatment plant will run different machines, but the records follow much the same order.

For each stage the useful question is not only what happens, but what record it leaves. Those records are what the customer asks for when a tube splits, and what tells the plant whether the job made money.

The process at a glance

1. 1Customer orderGrade, thickness, width, tolerance, quantity in tonnes and delivery date.
2. 2Routing and yieldInput item, output sizes, operations and the expected yield.
3. 3Material planningCoils in stock matched by grade and size; shortfall sent to purchase.
4. 4Procurement and receiptCoil received with heat number, weight and mill test certificate, and checked.
5. 5Production orderBatch planned on the slitter, coil issued by weight.
6. 6Slitting and cuttingOutput coils and sheets weighed, trim and scrap recorded by reason.
7. 7In-process inspectionWidth, burr, camber and surface checked at the machine.
8. 8Final QC and weighingEach finished lot checked, weighed and released or held.
9. 9Finished goodsReleased lots in stock by weight, pieces and heat number.
10. 10DispatchPicked against the order, heat number on the delivery note.

What happens at each stage, and what it records

1. Customer order

The tube maker orders narrow coils of a set width in a given grade, with width and burr tolerances, a coil weight limit and a delivery date. The order is usually in tonnes. The record should hold the grade, thickness, width, tolerances, quantity, unit and date, so what is produced can be checked against it.

2. Routing and expected yield

For this job the routing is short: slit, inspect, pack. The sheet part of the order adds cut to length and levelling. Six mults of 200 mm from a 1250 mm coil leave 50 mm of edge trim before anything else goes wrong, so the expected yield is known before the coil is loaded. Writing it on the routing gives every batch a figure to be measured against.

3. Material planning

The planner looks for coils in stock of the right grade, thickness and width that are not already promised to another order. If none fits, the shortfall goes to purchase with the date the slitter needs it. A coil allocated to this order should not show as free to anyone else.

4. Procurement and receipt

The coil arrives from the mill or a trader with a tag, a heat number and a mill test certificate. Stores weighs it and records the weight against the supplier's figure. Quality checks thickness and surface and compares the certificate values with the grade ordered. The record holds supplier, heat number, grade, dimensions, weight and the certificate values. A coil that fails is held.

5. Production order and issue

The batch is placed on the slitter for a shift, and stores issues the coil to it by weight. From here, everything that comes off the slitter is linked to this coil and its heat number.

6. Slitting and cutting

The setter sets the knives and spacers, runs the first few metres and checks the width before the full coil runs. Six narrow coils come off the recoiler and are weighed one by one. The edge trim is weighed as trim. Head and tail ends that are out of tolerance are weighed as setting loss. The operator records the output weights, the scrap by reason and any stoppage with its cause.

Two of the narrow coils go on to the cut-to-length line, where they are levelled and cut into sheets for the second customer. The sheets are counted and the stacks weighed, and the short end of each coil is either kept as a usable offcut or scrapped with a reason. Each stack keeps the heat number of the mother coil.

At the end of the batch, issued weight is set against output weight and scrap weight. The difference, if any, is a question for the shift, asked the same day. The guide on OEE monitoring for Indian manufacturers covers how downtime and rate losses on the same machine are read.

7. In-process inspection

QC checks slit width, burr height, camber and surface at the frequency the plan sets, and flatness and sheet length on the cut-to-length line. A failed check holds the batch until quality records re-trim, use as is, or reject. Catching a worn knife here saves the rest of the coil.

8. Final QC and weighing

Each finished coil or stack is inspected, weighed and labelled with its lot, size, weight and heat number. QC records the disposition with a name on it. A held lot cannot move to dispatch. Any rework, such as re-levelling a stack that failed flatness, is an operation on the same order with its own re-inspection and its own weight loss.

9. Finished goods

Released lots are received into the finished bay by lot, weight and pieces, against the order. Usable offcuts go to the raw material bay as their own lots with grade, size and heat number, so the next small order can use them. Lots that are counted but not received by lot are where the trace most often breaks.

10. Dispatch

Lots are picked against the order, loaded and weighed out. The delivery note carries each lot's weight and heat number, and the customer receives the certificate values for those heats. The invoice goes by weight. The record shows which lots went on which vehicle against which order line, which is where a complaint will start.

What to record and control at each stage

Where the process usually breaks

• At receipt, when the coil is weighed but the certificate values stay on paper.
• At issue, when a coil is taken from the bay without being issued to a batch, so the input weight is a guess.
• At the slitter, when output is weighed but trim and setting loss go into one scrap bin without a reason.
• At the cut-to-length line, when stacks are counted but the heat number is not carried onto their labels.
• At the vendor, when coils sent for pickling or galvanising come back at a different weight and nobody checks it against the challan.
• At dispatch, when the delivery note is written from the order, not from the lots actually loaded.

How is one lot traced back from dispatch?

If the tube maker reports splitting on tubes from one delivery, the trace runs backwards: delivery note to the narrow coil lots, each lot to its slitting batch, the batch to the mother coil, and the mother coil to its heat number, its mill certificate and its incoming check. Along the way it picks up the stage checks, the operator and the shift. If every stage wrote to the lot as it happened, the trace is read straight off the record. When the records are in registers and a box file, it becomes a search through the bays.

How FleekERP records each stage

FleekERP holds every stage above as a step on the work order. Coils are received by lot with the heat number and certificate values as characteristics, production planning places the batch on the machine against capacity and material, the coil is issued by weight, and the operator records output lots, scrap by reason and downtime from a phone. QC records stage checks with a hold on failure, vendor processing runs on a challan, and dispatch picks by lot with the heat number on the delivery note. The invoice syncs to Tally or Zoho. The metal processing industry page shows the same flow from the plant's side.

How the process differs by plant type

• Coil service centres: slitting and cut to length, with edge trim and head and tail loss as the main yield questions, and coil weight limits from the customer.
• Plate processors: profile cutting from plate, where usable offcuts are a large share of stock and have to be found again by grade, thickness and size.
• Bar cutting and bright bar: cut lengths from bar with end pieces as scrap or stock, and straightness and size checks.
• Forming and pressing: blanks from coil or sheet formed into sections or parts, with bend and dimensional checks and, sometimes, a multi-level BOM after forming.
• Heat and surface treatment: furnace or tank loads as the batch, hardness or coating checks, and often material owned by the customer and processed on job work.