Semi-Finished Goods: Should a Painted Frame Get Its Own Part Number?

More item codes feel like more control. Give the welded frame a number, the painted frame a number, and surely you will always know where things are. Often you won't. You will just have more bookings and stock counts to get wrong.

Semi-finished goods are intermediate products: parts that have been through some manufacturing steps but still need more work before they become a finished product. The real question is which of them deserve their own part number, and which should stay invisible inside the routing.

The three-question test for semi-finished goods

Give an intermediate its own item code when naming it changes what you make, reserve or move.

1. Make: Is it made in a different batch size or at a different time than the product that uses it?
2. Reserve: Can two orders compete for the same pieces?
3. Move: Does it sit somewhere, get counted, transferred or inspected between steps?

If all three answers are no, it is just a stage of work and belongs on the routing, not in the item master. If any answer is yes, the planner needs to see it.

Think of a kitchen. The onions you chop for tonight's sauce don't get a label. The stock you boil on Monday for the whole week does, because it is made on a different day, in a different quantity, and three dishes draw from the same pot.

Phantom vs stocked subassembly: one frame, two answers

Here is a simple two-level BOM for a steel workbench:

• Workbench WB-120 (1)
• Painted frame FR-120 (1)
• Steel tube 40×40 mm (2.5 m)
• Powder paint, blue (0.8 kg)
• Worktop 1200 mm (1)
• Screw kit (1)

Plant A welds and paints each frame and carries it straight to assembly. It is never stored and never counted. Here FR-120 should be a phantom: it appears in the bill of materials so engineering can see the structure, but MRP passes straight through it to the tube and the paint. No receipt, no issue, no stock balance.

Plant B paints in batches of 60 once a week, because the powder booth takes an hour to change color. Assembly builds 12 workbenches a day across three models that all use the same frame. Now all three answers are yes. FR-120 must be a stocked subassembly with its own manufacturing order and stock balance. Otherwise the planner can't answer the question that matters every morning: do we have frames for today's 12?

A batch of 60 used at 12 a day lasts five days. On average, 30 frames sit in stock. With an item code, you can see that stock and manage it.

Myth: "More item codes give you more control"

Every stocked intermediate adds at least two bookings per order: a receipt when it is made and an issue when it is used. Suppose Plant A gave its frames an item code anyway. At 200 orders a month, that is 400 extra transactions. At 3 minutes each, that is 20 hours a month of typing. And each late or missed booking creates a stock figure that is wrong, which then triggers a shortage that doesn't exist.

A phantom that nobody books is more accurate than a stocked item that is booked late.

A cable example: the insulated core

In cable manufacturing, the classic semi-finished good is the insulated core. Copper is insulated on an extrusion line and wound onto reels, which then feed stranding and sheathing.

Run the test. Make: the extrusion line runs long lengths in one color, much longer than any single cable order. Reserve: a blue 1.5 mm² core goes into both 3-core and 5-core cables, so orders compete for it. Move: reels wait next to the stranding machine and each reel has its own length. All three are yes, so the core gets its own item, and each reel should be tracked as its own batch with its remaining length.

Compare that with the stranded bundle before sheathing. In plants where stranding and sheathing run in tandem on one line, the bundle never exists on its own. It needs no item code.

Each core color and cross-section is its own item with its own norms per kilometer. How those norms are built from the cable's data sheet is shown in cable TDS, material norms and technology.

What goes wrong when you choose badly

• Too few codes: two assembly orders both look covered by one WIP total, and one of them stops. This is the classic missing part problem in assembly.
• Too many codes: stock of intermediates drifts away from reality because nobody books them on time, and planners stop trusting the numbers.
• The right codes, wrong status: a stocked subassembly that is waiting for inspection is counted as available. Semi-finished stock needs the same states as any other stock, as explained in inventory management for manufacturers.

How factory.online handles it

In factory.online, a stocked semi-finished item gets its own manufacturing orders, and MRP walks the multi-level BOM so the cable order creates a requirement for insulated core, linked to the order that caused it. Each reel can be a batch with its own length and location. For a 4 km run of 3-core cable, the planner sees a requirement of a little over 4 km each of brown, blue and green-yellow core, and which reels can supply it.

If your item list has grown faster than your control over it, book a demo and bring one product structure to test.