When sourcing die-cast parts from China, quotations from different suppliers can vary significantly even when the same drawing is provided.
The key is not to assume that the lowest quotation is automatically the best choice, or that a higher quotation is necessarily safer.
A practical comparison starts by breaking the quotation into six cost factors—material, casting, secondary processing, tooling, quality assurance, and logistics/commercial terms—and then aligning the assumptions used by each supplier.
Differences in quoted price often come from differences in assumptions such as:
- material price basis
- cavity count and cycle-time assumptions
- machining scope
- tooling cost treatment
- inspection scope
- packaging and logistics terms
Before comparing unit prices, first make sure the suppliers are quoting on comparable conditions.
1. Compare the assumptions before comparing the price
Even with the same drawing, suppliers may not be quoting exactly the same scope.
For example, one supplier may quote tooling separately while another amortizes part of the tooling cost into the piece price. One quotation may include machining and inspection, while another treats them as additional charges. Packaging and Incoterms may also differ.
At minimum, align the following items:
- alloy
- part weight
- annual volume and lifetime volume
- machining and surface-treatment scope
- inspection items and inspection frequency
- tooling ownership and maintenance conditions
- packaging
- Incoterms
- payment and currency assumptions
The basic rule is simple:
Align the quotation assumptions before comparing the prices.
2. Break the quotation into six cost groups
For practical sourcing work, a die-casting quotation can be reviewed as six main cost groups:
- Material cost
- Casting cost
- Secondary processing and finishing
- Tooling cost
- Quality-assurance cost
- Logistics and commercial terms
Looking at these groups separately makes it easier to understand why Supplier A may be lower than Supplier B.
3. Compare the assumptions behind material and casting costs
For material cost, part weight alone is not enough.
Useful items to confirm include:
- total metal charged per shot
- runner and overflow weight
- treatment of return metal
- material price reference date
The important question is:
What weight and material-price basis is the supplier using in the quotation?
For casting cost, it is more useful to review the supplier’s assumptions than to apply a generic industry cycle-time number.
Ask for:
- machine size or equipment used
- number of cavities
- assumed cycle time
- automation scope
- assumed good-part rate
Even for the same part, the cost per piece can change depending on whether the tool is single-cavity or multi-cavity and how much of the process is automated.
Also keep the definitions separate. Good-part rate, metal yield, and equipment utilization are different indicators and should not be treated as the same “yield” figure.
4. Clarify the scope of secondary processing and tooling
Die-cast parts may require additional operations such as:
- trimming
- deburring
- CNC machining
- tapping
- washing
- heat treatment
- painting or plating
- assembly
A quotation described as a “finished part” may still include a different process scope from another supplier’s quotation.
For CNC machining in particular, cost can vary with the machining features, fixture concept, number of operations, and inspection method.
Therefore:
Do not compare an as-cast price with a fully machined finished-part price as if they were equivalent.
The same principle applies to tooling.
Check whether the tooling quotation includes:
- main die
- inserts
- slides
- trim die
- fixtures
- trials
- modifications
- spare parts
- maintenance
Tool life should not be judged only by a fixed shot-count benchmark.
It is more useful to understand:
- which areas are expected to wear first
- whether inserts are replaceable
- repair conditions
- who pays for major repair or renewal
This gives a clearer picture of the real tooling cost over the project life. Reviewing the tooling scope and responsibilities before release is covered in reviewing the tooling scope before release.
5. Align the quality-assurance scope
Quality assurance also has a cost.
Depending on the product and risk level, this may include:
- visual inspection
- dimensional inspection
- CMM measurement
- leak testing
- X-ray inspection
- material analysis
- launch-control activities
- PPAP documentation
The goal is not to require the same inspection package for every part.
Instead, define:
- what must be inspected
- how often it must be inspected
- whether inspection is 100% or sampling
- what acceptance criteria apply
These conditions should be aligned at the RFQ stage.
ISO 9001 certification can be useful evidence that a supplier operates a quality-management system, but it does not by itself guarantee the quality or inspection frequency of an individual part.
6. Compare Total Project Cost, not only the lowest unit price
Total Project Cost means the overall project cost, including not only the unit price but also tooling, processing, inspection, logistics, and the cost of quality-related issues.
A low ex-works unit price does not necessarily mean the lowest final cost.
Additional costs may arise from:
- packaging
- international freight
- customs and duties
- domestic delivery
- sorting
- rework
- tooling modifications
- emergency freight
- additional inspection
A practical comparison can therefore use the following framework:
Total Project Cost
= Product purchase cost
+ Tooling and fixture cost
+ Secondary processing and inspection cost
+ Logistics cost
+ Quality-response cost
This is not a standardized formula. It is a practical framework for comparing suppliers on the same basis.
7. Compare the assumptions side by side
Instead of comparing only the quoted unit price, place the main assumptions side by side.
| Comparison item | Supplier A | Supplier B | Supplier C |
|---|---|---|---|
| Alloy | |||
| Cavity count | |||
| Assumed cycle time | |||
| Machining scope | |||
| Inspection scope | |||
| Tooling cost / maintenance scope | |||
| Packaging / Incoterms | |||
| Unit price |
This makes it easier to see why the quoted prices differ.
A lower price is not automatically a warning sign. A supplier may have a legitimate cost advantage because of higher automation, strong purchasing power, in-house tooling, or experience with similar parts.
The key question is:
Can the supplier explain why the price is different?
8. Minimum information to align in an RFQ
To make quotations easier to compare, define at least the following in the RFQ.
Product and process conditions
- drawing and 3D data
- alloy
- volume and lifetime volume
- machining scope
- surface treatment
- assembly and washing
Quality conditions
- critical dimensions
- appearance and leak requirements
- internal-quality requirements
- inspection method and frequency
- required initial-approval documents
Tooling and commercial conditions
- tooling ownership
- trial and modification conditions
- maintenance and renewal conditions
- Incoterms
- packaging
- payment terms
- price-adjustment rules
With these conditions aligned, the decision becomes less about whether a quotation is simply “cheap” or “expensive” and more about which proposal is the most reasonable under the same assumptions.
Summary
Key points for comparing quotations
- Align the quotation assumptions instead of comparing unit price alone.
- Break the quotation into six factors: material, casting, secondary processing, tooling, quality assurance, and logistics/commercial terms.
- Make the final decision using Total Project Cost.
When sourcing die-cast parts from China, the objective is not simply to find the lowest unit price.
The important point is to understand the assumptions behind each quotation and compare suppliers on a common basis.
Ultimately, the most useful question is:
Can the supplier clearly explain why the quotation is at that price?
Next Step: Compare Quotations on the Same Technical Basis
When comparing quotations from multiple Chinese suppliers, align more than the unit price. The drawing, alloy, tooling scope, machining, surface treatment, inspection, volume and logistics assumptions should be compared on the same basis.
Start with the technical RFQ requirements before quotation to check whether important conditions or supplier assumptions are missing.
For the role of X-Diecasting Tech and the commercial framework used for China sourcing support, see our China sourcing principles.
If you are comparing quotations from multiple Chinese suppliers, you can share the drawing, volume, alloy, required secondary operations and the quotation conditions you would like to clarify. You can then discuss a drawing or sourcing project.
Frequently Asked Questions
Q1. What should I check first when Chinese die-casting suppliers quote very different prices?
First check whether the quotation assumptions are the same. Material, machining scope, inspection scope, tooling cost, packaging, and Incoterms may differ. If the conditions are different, unit prices cannot be compared fairly.
Q2. How should tool life be compared between suppliers?
Do not rely only on a fixed shot count. Review the tool steel, heat treatment, cooling, expected wear areas, replaceable inserts, repair conditions, and renewal responsibilities. The important point is how the tool-life assumption was established.
Q3. Does ISO 9001 certification mean the supplier’s product quality is assured?
No. ISO 9001 is useful evidence that a supplier operates a quality-management system, but it does not guarantee the quality of an individual part. Process capability, inspection methods, and actual quality performance should also be reviewed.
Q4. Should I select a Chinese die-casting supplier simply because the price is lower than sourcing in Japan?
No. A lower unit price alone is not enough to make the decision. First align the machining scope, inspection conditions, tooling cost, logistics terms, and quality-response assumptions, then compare Total Project Cost together with mass-production quality and delivery risks.