If you work in manufacturing, you've probably heard phrases like:
"This is a semi-finished product"
"Please check the semi-finished product inventory"
"We'll feed the semi-finished product into the next process"
If you've just joined a manufacturing company, you might wonder:
"What exactly is a semi-finished product?"
Some people picture "a product that's half finished" just from the name.
That's not far off.
But in manufacturing, a semi-finished product isn't just "something in the middle of being made."
In this article, we'll explain **"semi-finished products (半製品, hanseihin)"**, a term used in manufacturing, in a way that's easy for beginners to understand.
What Is a Semi-Finished Product?
Put simply, a semi-finished product is:
An intermediate product that is managed as its own distinct item, at a stage before it becomes a finished product
That's the basic idea.
For example, say making product A involves the following process.
材料
↓
加工
↓
中間製品B
↓
組立
↓
製品A完成
Intermediate product B is not yet the final product A.
It's not a finished product ready to be sold to a customer as-is — it still needs to go through further processes such as assembly.
However, intermediate product B is sometimes counted and tracked in inventory as a single item, like this:
中間製品B：500個
An intermediate product managed this way is called a semi-finished product.
A Semi-Finished Product Is "A Product Completed Partway Through"
To understand a semi-finished product, it helps to think of it as:
Something that has been cut off at a certain point in the manufacturing process
That framing makes it easier to grasp.
For example, suppose there's a manufacturing process like this.
工程1：加工
↓
工程2：組立
↓
工程3：検査
↓
完成
Whatever comes out of process 1 doesn't necessarily flow straight into process 2 right away.
工程1完了
↓
100個保管
↓
後日、工程2で使用
This kind of situation can happen.
When these 100 units are managed as an independent item, they may be handled as a semi-finished product.
In other words, a semi-finished product is:
Something not yet finished, but that can be handled as a single, self-contained unit partway through the manufacturing process
That's the idea.
Let's Think About It Using Clothing Manufacturing as an Example
Let's take garment manufacturing as an example.
Say making a shirt involves the following process.
生地
↓
裁断
↓
縫製
↓
ボタン付け
↓
検品
↓
完成
The fabric is the material.
A shirt that has been through every process is the finished product.
So what about fabric that has finished the cutting process?
For example, suppose it's managed like this:
シャツA用 裁断済み生地：1,000セット
tracked and kept in stock by quantity as a single item.
Afterward, this cut fabric is fed into the sewing process.
裁断済み生地
↓
縫製工程
↓
シャツ
When this cut fabric is managed as a distinct item, it may be handled as a semi-finished product.
Depending on the company, it might go by a different name, such as "cut piece" or "intermediate piece."
Semi-Finished Products Are Managed as Inventory
One key feature of semi-finished products is that they can be tracked as inventory.
For example, say you hold inventory like this:
半製品B：500個
Making one unit of product A requires one unit of semi-finished product B.
In that case, manufacturing looks like this:
半製品B 100個
↓
組立
↓
製品A 100個
When product A is manufactured, the semi-finished product B inventory decreases.
半製品B
500個
↓
100個使用
↓
400個
And the inventory of product A increases.
製品A
0個
↓
100個完成
↓
100個
In this way, a semi-finished product can play a role similar to a material used in the next manufacturing process.
What's the Difference Between a Semi-Finished Product and a Material?
"If it's used in the next process, isn't it the same as a material?"
You might be thinking that.
It's true that, viewed from the next process onward, a semi-finished product looks just like a material.
However, the big difference is whether it has already passed through your own company's manufacturing process.
For example, suppose:
仕入先から生地を購入
↓
裁断
↓
裁断済み生地
is the case.
The fabric you purchased is a material.
Fabric that your own company has cut has already passed through one step of your manufacturing process.
When this cut fabric is managed as its own independent item, it may be treated as a semi-finished product.
In other words:
A material = something that becomes the starting point fed into manufacturing
A semi-finished product = something that has already passed partway through the manufacturing process
Thinking of it this way makes it easier to understand.
The Difference Between Semi-Finished Products and Work-in-Process
A term that's especially easy to confuse with semi-finished products is **work-in-process (仕掛品, shikakarihin)**.
Neither one is a finished product yet.
That's exactly what makes the difference hard to grasp.
Put simply:
Work-in-process is "something still in the middle of being manufactured"
A semi-finished product is "something that has finished a process partway through and is managed as a single item"
That's the distinction.
For example, suppose there's a flow like this:
材料
↓
加工中
↓
加工完了
↓
保管
↓
次工程
Something still being processed is work-in-process.
On the other hand, once processing is finished and until it's fed into the next process, anything managed like this:
半製品B：500個
can be considered a semi-finished product.
It's Easier to Understand Through Bread-Making
Let's use bread-making as an example.
Say the process for making bread is:
材料を混ぜる
↓
生地をこねる
↓
成形
↓
焼く
↓
完成
Dough that is being kneaded right now, in the middle of the process.
This is the image of work-in-process.
On the other hand, suppose dough that has finished being shaped is frozen and kept as:
冷凍パン生地：1,000個
held in stock this way.
Whenever needed, the frozen dough is taken out and baked into bread.
This frozen bread dough is closer to the image of a semi-finished product.
In other words:
Work-in-process = something currently being made, right now
Semi-finished product = a state where production has finished up to a point and it can be managed as a distinct item
That's the image to keep in mind.
The Boundary Between Semi-Finished Products and Work-in-Process Differs by Company
One thing worth noting here is that the boundary between semi-finished products and work-in-process isn't the same at every company.
For example, some companies manage cut fabric as:
半製品
while others manage it as:
仕掛品
What matters is whether that company:
Manages it as an independent item
Tracks the quantity as inventory
Where in the process it draws the line
These are the points that matter.
So if the term "semi-finished product" comes up in your work, it's a good idea to check:
"At this company, which completed process is called a semi-finished product?"
Why Manage Semi-Finished Products?
Managing semi-finished products lets you see how much of what exists partway through the manufacturing process.
For example, say the inventory of finished product A is 0 units.
But suppose there are:
半製品B：1,000個
in stock.
If product A can be made from semi-finished product B in a short time, you might be able to judge that
"there's no finished-product inventory, but 1,000 units can be made right away."
On the other hand, if:
完成品A：0個
半製品B：0個
then manufacturing needs to start from an even earlier process.
By looking at semi-finished product inventory this way, you can grasp:
Where in the manufacturing process things stand, and how much of it there is
That's what it lets you understand.
In Systems, Semi-Finished Products Can Also Be Registered as an "Item"
In production management systems, semi-finished products are sometimes registered as an item too.
For example:
品目コード：RM-001
品目名：生地A
種類：材料
品目コード：SF-001
品目名：裁断済み生地A
種類：半製品
品目コード：FG-001
品目名：シャツA
種類：完成品
structured this way.
And it manages the manufacturing process like this:
生地A
↓
裁断
↓
裁断済み生地A
↓
縫製
↓
シャツA
Managing semi-finished products as items makes it easier to check things such as:
- The inventory quantity of the semi-finished product
- When it was manufactured
- Which process it was made in
- Which product it will be used in next
and so on.
Summary
A semi-finished product is:
An intermediate product that is managed as its own distinct item, at a stage before it becomes a finished product
That's what it means.
It exists somewhere between material and finished product.
材料
↓
半製品
↓
完成品
A semi-finished product is not yet a finished product.
However, it has completed a certain manufacturing process and is managed as inventory, such as:
半製品A：500個
in this way.
In a nutshell:
A semi-finished product = something that has finished up to a point partway through and can be managed as a single item
That's what it is.
It's similar to work-in-process, but:
Work-in-process = something in the middle of being manufactured
A semi-finished product = something that has finished a process partway through and is managed as its own distinct item
Thinking of it this way makes it easier to understand.
That said, the boundary between semi-finished products and work-in-process differs by company.
If you've just joined a manufacturing company and come across the term "semi-finished product," try checking:
"Which process does this consider finished?"
"Is it managed as a distinct item or as inventory?"
Doing so will make the meaning of "semi-finished product" easier to grasp.