Discrete or Process Manufacturing: What’s the difference?

Amid ongoing global supply chain challenges, supply chain management continues to occupy centre-stage, and supply chain practitioners remain in the spotlight. Over the last two years or more, supply chains have been a recurring news story and there are no signs of that changing any time soon as almost a quarter of businesses expect their supply chain issues to still be a problem next summer. 

As supply chain leaders look to overcome these challenges, they can’t underestimate the importance of getting the basics right. 

So, with that, let’s revisit the two most common manufacturing processes: discrete and process manufacturing, to remind both seasoned veterans and newer supply chain professionals of when each should be used and how to improve both processes. 

What is Discrete Manufacturing?

Discrete manufacturing refers to the methods of production used to make individually identifiable “widgets” – subassemblies or finished products. These can include everything from laptops and phones to cars, boats, planes, machinery, and medical devices and span multiple industry verticals like high-tech electronics, automotive and industrial goods. However, they also exist in verticals like consumer goods and life sciences, despite these often being considered “process manufacturing”.

When it comes to the manufacturing process, it largely consists of assembling parts, subassemblies or components. Information or data constructs called bills-of-material (BOM) provide the list of subassemblies and parts, identified by part numbers, so the right components are used. 

As well as being individually identifiable, often through a unique identifier such as a serial number, the end product can usually be disassembled into its major parts.

Discrete manufacturing constraints

Manufacturing constraints tend to focus on material availability, rather than labour, given the high level of automation involved. As such, planners focus on material coordination – in other words, ensuring all needed parts are available at the right time so assembly can continue unimpeded. 

Resource capacity is consequently a major consideration, which is simply expressed in the number of units of production, and means resource changeover considerations don’t tend to be an issue, unlike with process manufacturing. As a result, concepts like production wheels or rhythm wheels are of little to no importance. 

Similarly, parts and subassemblies have much longer useful lifespans than perishable items like food and beverage ingredients. Consequently, attributes like shelf-life, expiration dates, and perishability don’t play a major role in planning.

Process Manufacturing

So, how exactly does process manufacturing differ? Process manufacturing refers to methods of production used to make bulk goods, like food, beverage, chemicals, pharmaceuticals, fertilisers, and metal products. These products are usually made in batches, identified by batch numbers, and measured in units of weight, volume or length. 

As you might have guessed from the types of products, process manufacturing methods are commonly found in the food and beverage, consumer goods, life sciences, chemicals and metals, and mining industries. However, the products also feed into all kinds of “discrete manufacturing”, including high-tech electronics, home appliances, and medical devices. While the upstream production processes are very distinct from discrete manufacturing processes, downstream steps like bottling and packaging share attributes with discrete processes.

And, unlike discrete manufacturing, process manufacturing tends to comprise biological or chemical processes such as mixing, blending, baking, curing, and moulding. Recipes and methods specified in detail what ingredients should be used and how they should be treated. Following those methods, the input materials or ingredients are changed in form, often irreversibly, into a finished product. This means that as production proceeds, the resultant products can no longer be separated out into their ingredients.

Process Manufacturing Constraints

Process manufacturing constraints primarily come down to the availability of time on resources such as mixers, blenders, ovens and bottling lines, as well as product changeover time and cost. In this scenario, capacity is usually stated and consumed as units of time, whether that’s days, hours or minutes. 

 As important as raw material or ingredient availability is, it is often overshadowed by resource utilisation considerations. For instance, rules govern the order in which different products can be produced on the same resource and what procedures must be followed in between products. As a result, considerable resource time can be lost through cleaning and retooling between dissimilar products, impacting a plant’s ability to meet demand as well as costs, and thereby impacting profitability. These costs are commonly represented as a changeover matrix that specifies the time and cost of transitioning from one product to another. 

Dynamic production wheel algorithms, such as Replan’s, take these complex changeover matrices into account along with basic demand, supply, inventory, and capacity statements to determine the optimal production sequence that best balances all the business objectives.

With this, raw material and ingredient perishability attributes, such as produced date, expiration date, and shelf-life, become important planning considerations.

Ensuring robust processes

As we can see, both discrete and process manufacturing carry their own distinctive characteristics. But most product supply chains and manufacturing processes include a mix of both discrete and process manufacturing, owing to a need for different components or parts to be made differently. 

As organisations look to increase efficiencies and increase supply chain resilience, a strong production planning solution is needed to provide strong capabilities and features to model discrete and process manufacturing processes and easily configurable algorithms that can optimise, balance and synchronise inventory, capacity, and service.

To discuss how these characteristics impact your production planning processes and solutions, get in touch with our expert team.

Discrete v. Process at a glance

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