3 scheduling principles for a digital planning board for job shops

    September 30, 2021
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    A job shops' production process differs greatly from other production companies - they are small, they produce highly customized products, they start planning exclusively according to a customer's order, the job routings can barely be standardized, the batch size is small.

    Scheduling the jobs is a Herculean task.

    More and more job shop owners understand that Excel is not the right choice if they want to bring more efficiency to their production process. They need some scheduling automation best combined with a digital planning board.

    But what kind of automation is suitable for the special need of job shops? Here are 3 scheduling principles that job shop scheduling should be based on and that therefore need to be reflected in a suitable software tool for them. 

    Principle 1: priority-based job scheduling

    Job shops work with an order list where they always add new orders at the bottom. This results in a priority-based scheduling system. The top order has the highest priority and therefore the priority number 1 (we call it sequence number, btw), the last order the lowest.

    Of course, the last accepted order is not necessarily processed last. It can be moved up to a higher position in the list if faster processing is desired, and accordingly, the other jobs below fall further down. So, reschedule means changing the job's priority (and thus the sequence number) and the job shop scheduling algorithm recalculates the new sequence of the jobs as well as their tasks.

     job shop scheduling principle - priority based scheduling

    Principle 2: forward scheduling of tasks

    Forward scheduling means that the primary objective is to start a task as soon as possible. Starting production early allows space for unexpected disruptions in the process. 

    job shop scheduling priciple - forward scheduling

    Principle 3: finite capacity scheduling

    The production method of job shops is typically very labor-intensive and little automated. They work with a very well-trained workforce, which they can flexibly deploy at multiple workstations in the production process. So the calendar reflecting the employees' days off and working hours, as well as their qualifications, is a limiting factor when calculating the resource allocation for the production schedule.

    Finite capacity scheduling is, therefore, an important principle for production scheduling tools for job shops.

    Scheduling principles for job shop production - finite capacities

    Further readings

    The Theory of Constraints and its application to job shop scheduling

    What is flow shop scheduling vs job shop scheduling

    30% decrease in WIP with purpose-built software for HMLV manufacturer

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