In short
- Most delivery slippage traces to material availability and unplanned changeover, not machine speed.
- Plan from the OEM firm horizon, and let MRP net raw, bought-out and sub-contract material in one pass.
- Sequence to minimise die and setup changes, because changeover is real capacity consumed.
- Show line load before committing a date, or the date is a guess.
Why automotive delivery dates slip
Ask a Hosur supplier why a shipment was late and the answer is rarely that machining was slow. It is that the steel or bought-out part arrived late, that a die was on another job, that plating took three days longer than assumed, or that three parts were promised the same week without anyone comparing them to capacity.
All four are planning failures rather than production failures. They happen because the plan lives in a spreadsheet and a supervisor's memory rather than in a system that can net requirements against reality and show load honestly.
Plan from the schedule, not from history
The build plan should be generated from the OEM firm horizon rather than from last month's output. When the schedule revises, the plan regenerates and the changes that matter are highlighted.
Practically this means firm quantities drive work orders while forecast quantities drive material commitment. Standard high-runner parts may run to a stock level; low-volume or engineered parts route to order. The routing decision should be automatic at release rather than a daily judgement call, which removes a large amount of the ad hoc replanning that consumes a planner's day. Our planning page covers the structure.
See how this runs on your own part numbers, schedule to dispatch.
MRP that reflects an automotive supply chain
A useful MRP run nets requirements across everything the build consumes, in one pass:
- Raw material, coil, bar or resin, with supplier lead time.
- Bought-out components, often the longest lead and least controllable.
- Sub-contract operations, plating, heat treatment and outside machining, each with lead time.
- Material lying at job work vendors, which is inventory you own and must be counted.
- Line-side stock, which is frequently the largest source of book-to-physical variance.
The last two are what spreadsheets most often get wrong, and both cause the same failure: reordering material you already have while a different part stocks out.
Changeover is capacity
In a press or machining shop, changeover is not overhead around production, it is production time consumed. A plan that assumes instant switching between parts will always be optimistic.
Sequencing that groups similar setups, shares dies where possible and orders the week to minimise changes recovers real capacity without any capital spend. The trade-off is inventory: longer runs mean more stock. The right balance depends on your schedule stability, and it should be an explicit decision rather than an accident.
| Constraint | Symptom when ignored |
|---|---|
| Raw and bought-out supply | Line idle waiting on material |
| Press and CNC capacity | Queue grows silently |
| Die and tooling availability | Job cannot run despite free machine |
| Sub-contract lead time | Parts stuck at plating before final ops |
| Inspection and dispatch | Finished parts waiting to ship |
Want a fixed-scope ERP plan for your Hosur plant?
A planning rhythm
- On schedule receipt: load, compare, flag changes and new shortages.
- Weekly: run MRP, release work orders, check load and changeover sequence, confirm commitments.
- Daily: short review of yesterday's output, today's exceptions and anything stuck at a sub-contract vendor.
- At commitment: promise dates drawn from actual capacity.
The daily review matters more than the software. Fifteen minutes with the plan visible catches problems while they are still cheap.
Measuring whether it works
- On-time delivery against first promise, not against a revised date.
- Schedule adherence, how much of the planned week was actually built in that week.
- Material availability at work order release, which usually explains the other two.
- Changeover hours as a share of available capacity.
Track them weekly on a dashboard rather than compiling at month end. See analytics.
Key Takeaways
- Delivery slippage traces to material availability and unplanned changeover far more often than to machine speed.
- Generate the build plan from the OEM firm horizon and regenerate cleanly on revision.
- MRP must net raw, bought-out, sub-contract and vendor-held material in one pass.
- Changeover is capacity consumed; sequencing to reduce it recovers real hours without capital spend.
- Show line load before committing a date, and measure on-time delivery against first promise.
Frequently Asked Questions
Material availability and unplanned changeover, compounded by commitments made without reference to real capacity.
From the OEM firm horizon. Planning from historical output means responding to your own past rather than to the customer's actual demand.
Yes. It is inventory you own. If MRP cannot see it you will reorder material you already have while something else stocks out.
As capacity consumed. Sequencing that groups similar setups recovers real hours, with the trade-off being slightly higher inventory from longer runs.
Far enough to cover your longest lead time, usually a bought-out component or sub-contract operation, with weekly release and daily review inside that horizon.
Give whoever commits the date visibility of load for that week at the point of commitment. Most unrealistic promises are made in good faith without that information.
Material availability at work order release, because it usually explains both schedule adherence and on-time delivery.
Usually not first. Most plants find capacity already exists but is lost to waiting for material, changeover and rework.
Material availability and schedule adherence typically move within one or two planning cycles; on-time delivery follows within a quarter.
Yes, as routed operations with their own lead time, so plating or heat treatment appears in the plan rather than as a surprise.
Conclusion
Production planning is where most auto-component suppliers have the largest unclaimed gain, because the constraint is rarely the machines. It is knowing what material you truly have including what sits at a plating vendor, what changeovers the week actually requires, and whether this week's commitments fit inside this week's hours. Plan from the schedule, run an MRP that reflects a real automotive supply chain, sequence to protect capacity, and hold a short daily rhythm around a visible plan. None of that requires capital investment.
Want a plan your shop floor can actually hold?
Talk to our Hosur team, or book a free demo and see it on your own part BOM.