Automotive manufacturing process: from BOM to dispatch

The stages below follow one typical part: a steel flange that is turned and drilled, zinc plated by a vendor, then pressed together with a bush into a sub-assembly for an OEM. A press shop or a casting plant will have different operations, but the sequence of records is much the same.

For each stage, the useful question is not only what happens, but what record it leaves behind. Those records are what a customer asks for when something goes wrong.

The process at a glance

1. 1Customer orderOEM schedule lines become sales orders by part and delivery date.
2. 2BOM and routingThe released revision is fixed on the work order.
3. 3Material planningNeeds are compared with stock by lot and open purchase orders.
4. 4ProcurementBar and bushes are bought, received by lot and inspected on arrival.
5. 5Production orderThe order is planned on work centres and material is issued by lot.
6. 6Machining and operationsFirst-off approval, then counts, scrap and downtime per operation, plating at the vendor and the sub-assembly press.
7. 7In-process inspectionControl plan characteristics measured at the operation.
8. 8Final QCSample plan on the finished lot, then release, rework or reject.
9. 9Finished goodsReleased lots received into stock against the order.
10. 10DispatchPicked by lot against the schedule, shipped with a delivery note.

What happens at each stage, and what it records

1. Customer order and schedule

OEMs send delivery schedules, often weekly, with firm quantities for the near term and a forecast beyond. Each line becomes a sales order line by part number and delivery date. The record should hold the part number and revision, quantity, due date and the schedule it came from, so a later revision can be compared with it.

2. BOM and routing

The BOM lists the steel bar, the bush and any consumables. The routing lists the operations in order: turning, drilling, deburring, plating at the vendor, pressing the bush, final inspection. The revision released to the order should be fixed on it, so a drawing change later does not alter what was made. The guide to multi-level BOM management covers this in detail.

3. Material planning

Requirements from all open orders are compared with stock by lot and with open purchase orders. A useful shortage report names the order it will stop and when, so purchasing knows which supplier to chase first.

4. Procurement and incoming inspection

Bar stock arrives with a mill test certificate and a heat number. Bought-out bushes arrive by supplier lot. Incoming inspection samples each lot before it is accepted, and a failed lot is held. The record holds the supplier, the lot or heat number, the quantity and the result.

5. Production order release

The work order is placed on work centres according to their capacity, and stores issues material to it by lot. From this point, every count and check on the order is linked to the material inside it.

6. Machining and operations

At setup, the first part off the machine is measured against the drawing and approved before the batch runs. During the run, operators log good counts, scrap with a reason and downtime with a cause, against the operation. The record shows what each operation made, by operator and shift.

Not every operation is in-house. The machined flanges go to a plating vendor on a challan and come back against it, where they are counted and checked. The record holds the quantity sent and returned, any short or rejected quantity, and the vendor's charge, which belongs on the order's cost.

The plated flange and the bush are then pressed together. The sub-assembly lot records both component lots it consumed, so the genealogy continues through the assembly rather than stopping at it.

7. In-process inspection

Characteristics from the control plan, such as a bore diameter, a face runout or a thread check, are measured at the frequency the plan sets. A failed check holds the batch until quality records rework, use as is, or reject. Catching it here, rather than at final inspection, is what keeps one bad setting from spoiling a whole shift's output. The article on reducing rejection by inspecting at the operation explains why.

8. Final QC and release

The finished lot is inspected on a sample plan, and the results are kept for the customer. QC then records the disposition: release, rework, use as is, or reject, with a name on it. A held lot cannot move to finished goods or dispatch until it is dispositioned, and any rework is recorded as an operation with its own re-inspection.

9. Finished goods

Released lots are received into the finished goods store by lot, against the order. This is the stock dispatch picks from, so it should show what is released, what is still on hold, and how much is available against each open schedule line. Finished goods that are counted but not received by lot are where the trace most often breaks.

10. Packing and dispatch

Lots are picked against the schedule, packed to the customer's standard and shipped with a delivery note and invoice. The record shows which lots went against which schedule line, which is where a customer complaint will start.

What to record and control at each stage

Where the process usually breaks

• Between schedule and plan, when a revised schedule is not carried into the work orders.
• At material issue, when stock is issued without a lot, so the genealogy has a gap from the start.
• At in-process inspection, when checks are written on paper and never linked to the batch.
• At the vendor, when returns are not counted against the challan and short quantities go unnoticed.
• At assembly, when component lots are not recorded against the sub-assembly lot.

How is one lot traced back from dispatch?

If a customer reports a failure on parts from one delivery, the trace runs backwards: delivery note to finished lot, finished lot to its sub-assembly and component lots, each lot to its operations, operators and inspection values, and finally to the supplier lot and heat number. When each stage left its record on the lot, this is a lookup. When the records are on paper or in separate files, it becomes an investigation.

How FleekERP records each stage

In FleekERP each stage above is a step on the work order. Schedule lines become sales and work orders. Production planning places orders on work centres against capacity and material readiness. Stores receives and issues by lot, operators and QC record counts, scrap, downtime and measured values from their phones, the plating step sits on the routing with its challan, and dispatch picks by lot. The invoice syncs to Tally or Zoho. The automotive industry page shows the same flow from the plant's point of view.

How the process differs by plant type

• Machining plants: deeper routings, setup and first-off approval at every operation, and cycle time as the main capacity driver.
• Press shops: coil and sheet received by heat number, die changes as planned time, and material yield from the strip.
• Assembly lines: many component lots per finished unit, so recording which lots went into which assembly lot matters most.
• Casting and forging: melt or heat batches as the first lot, with heat treatment often done by a vendor.