Make-to-Order Production Planning in 5 Steps: From MRP to Queues

By P-Soft Expert Team October 10, 2026 9 min read

Make-to-order production planning takes five steps: review the order before accepting it, derive the bill of materials and material requirements, estimate the load on each machine, set the sequence of work, and turn the plan into each operator’s work queue. Skip any one of them and the delivery date you give the customer is only a guess.

Most production planning material is written for factories with standard products and a sales forecast. In a job shop where a new customer drawing lands every week, forecasting demand does not help much. The real question is: “With the orders on the table right now, what should we make, when, and on which machine?” This guide is a practical method for answering that question, along with the mistakes that cause the most delays.

How Is Make-to-Order Planning Different From Make-to-Stock?

Topic	Make-to-stock	Make-to-order
Where the plan starts	Sales forecast	A confirmed customer order
Bill of materials	Fixed and proven in advance	Often prepared fresh for each order
Routing	Repetitive	May differ for every part
Main goal	Lower cost and inventory	Hitting the promised delivery date

The consequence is simple: in custom manufacturing, planning starts at the moment you quote, not when the work order is released.

Step 1: Review the Order Before You Accept It

The best place to prevent a delay is before the contract is signed. We recommend reviewing every order from these five angles, each with a named owner:

Technical: is the drawing complete, and can the plant hold the required tolerances and material?
Pricing: is the price based on actual materials and operations?
Planning: given the current machine load, is the proposed date achievable?
Outsourcing: which operations must be done outside, and is that subcontractor available?
Production: what execution risks does the shop floor supervisor see?

The output of this step is an approved order with a clear routing. If any of the five opinions is negative, fix the date or the price before you accept.

Step 2: Bill of Materials and Material Requirements (MRP in Plain English)

MRP, or material requirements planning, answers three questions: which materials are needed, how much, and by when. In make-to-order work, this calculation is done separately for each order:

From the drawing, write the part’s bill of materials (BOM): raw materials, purchased components and sub-assemblies.
Work out the quantity of each line, allowing for cutting and machining waste.
Subtract unallocated stock; material already reserved for another order is not available.
Raise purchase requests for shortages and build their arrival time into the plan.

If terms such as BOM, stock card or issue slip are unfamiliar, the Barsavosh glossary has short definitions.

Step 3: Machine Capacity and Workload

For every operation on the part’s routing, note the approximate setup and run time and assign it to the right machine. Add up the load from all orders and the bottleneck becomes obvious. A hypothetical example:

Machine (hypothetical)	Hours available this week	Hours required by orders	Status
CNC mill	80	95	Bottleneck; 15 hours short
Lathe	80	50	Spare capacity
Grinder	40	38	Nearly full

In this example you have three options: overtime on the mill, outsourcing part of the milling, or moving the date of an order whose customer is flexible. What matters is making that call before the week starts, not after work has already slipped.

Step 4: Job Sequencing

Once machine loads are clear, you have to decide which job goes first. A few common rules in industry:

Earliest due date: the order with the nearest date goes first; simple and easy to defend.
Critical ratio: the order with the least time left relative to the work remaining gets priority.
Grouping similar setups: jobs that share tooling or fixtures run back to back to cut setup time.

No rule is always best. Most factories adopt one main rule, such as due date, and allow exceptions only in special cases. Record each exception with its reason so it can be reviewed later.

Step 5: Turn the Plan Into Operator Work Queues

A plan that stays on the planner’s desk does not get executed. Every operator needs to know their next job, where its drawing and specs are, and where to log the report when they finish. Supervisors need to see all operators’ queues and reshuffle the order if a machine breaks down or material runs short. The report at the end of each stage is the input to the next day’s plan; without that feedback, the plan drifts away from reality on the floor within a couple of days.

A Hypothetical Example: 40 Flanges From Drawing to Work Queue

Suppose a customer sends a drawing for a steel flange and wants 40 pieces in three weeks (all numbers are hypothetical):

Review: engineering confirms the tolerances are achievable on the existing lathe and mill, but galvanizing must be done outside and the subcontractor needs about a week. So three weeks works only if machining is finished in the first two.
Material requirements: the bar stock needed is calculated including waste; the warehouse has half of it unallocated, and a purchase request is raised for the rest.
Capacity: the lathe has spare capacity in week one, but the mill is the bottleneck; the planner moves the milling to the start of week two and pushes back an order with a flexible due date.
Sequencing: because the flanges share a setup, all 40 run back to back on each machine.
Work queue: the lathe operator sees the job in Monday’s queue and logs a report after each stage, so the planner knows when parts will reach the mill.

In this example the delivery date was checked before the order was accepted, not after. That difference is what separates a reliable promise from a guess.

How Does Production Planning Software Help?

You can start these five steps with paper and Excel, but as orders grow, keeping material requirements, machine loads and the status of every order in your head becomes hard. Good production scheduling software for a job shop should at least connect order review, the bill of materials, operator queues and stage reports.

For example, in Data, the manufacturing ERP from Barsavosh, the Pro plan includes multi-stage order review (technical, pricing, planning, outsourcing and production), materials and operations for each part, a production plan with material requirements and a schedule for each order, “ready for planning” and “ready for outsourcing” lists, and operator and supervisor work queues; a busy/idle view of each machine and an operator panel on a tablet are added in Elite. Data runs on the factory’s own server and its interface is in Persian. For the full capability comparison, see our make-to-order ERP page.

Common Mistakes in Job Shop Scheduling

Promising delivery before looking at machine load: sales gives a date and the planner has to justify it later.
Treating total stock as available stock: material reserved for another order gets counted again.
Forgetting outsourcing time: the round trip to the subcontractor is part of the order’s routing and belongs in the schedule.
Planning to 100% of capacity: with no margin for breakdowns and rush jobs, the first surprise wrecks the whole week.
No feedback from the floor: when stage reports are logged late, tomorrow’s plan is built on yesterday’s data.
Separating quality from planning: a part that fails inspection and is reworked takes capacity again; our guide to production quality control shows how to handle it.

Weekly Checklist for the Production Planner

Add newly approved orders to the planning list.
Check each order’s material shortages with the warehouse and purchasing.
Calculate next week’s load on the bottleneck machines.
Follow up outsourced work with a clear return date.
List overdue orders with the reason for each delay.
Update operator work queues and share them with the supervisor.

Frequently Asked Questions

Does MRP apply to make-to-order production?

Yes, with one difference: material requirements are calculated per order from that order’s bill of materials, not from a sales forecast.

What is the best rule for sequencing orders?

There is no single rule for everyone; earliest due date is a simple starting point, and exceptions should be recorded with a reason.

How much machine capacity should we plan?

There is no fixed number, but planning all capacity with no margin for breakdowns and rush work usually leads to cascading delays.

Do we need software to get started?

No. The method works with paper and Excel, but it becomes hard to maintain by hand as the number of orders grows.

Which Data plan includes production planning?

Production planning, material requirements and operator work queues are included from the Pro plan.

To see these steps applied to your own factory’s orders, explore Data manufacturing ERP and request a demo.