Quick Answer
To receive an accurate injection mold quotation, buyers should prepare the product drawing, plastic material, part dimensions, part weight, annual production quantity, cavity requirements, surface finish, tolerance requirements, injection molding machine information and any special mold standard.
A 3D drawing alone is usually not enough.
The mold supplier needs to understand not only the plastic part shape, but also how the part will be produced, assembled, inspected and used in real production.
A complete RFQ package helps reduce quotation errors, avoid later design changes and shorten communication time.
Why a Complete Mold RFQ Package Matters
Many mold quotation delays are caused by incomplete information.
A buyer may send only a product photo and ask:
“How much is this mold?”
In most cases, the mold supplier cannot provide a reliable answer from a photo alone.
Injection mold cost depends on many factors, including:
- Product size
- Plastic material
- Part weight
- Number of cavities
- Mold steel
- Runner system
- Slider and lifter structure
- Surface finish
- Mold life requirement
- Tolerance requirement
- Required cycle time
- Injection molding machine specification
- Export mold standard
If important details are missing, the supplier may either quote too high to cover risk, or quote too low and later request additional cost after mold design begins.
A clear RFQ package protects both the buyer and the mold supplier.
Minimum Information Required for an Injection Mold Quote
The following information should be prepared before requesting a custom plastic injection mold quotation.
| Information | Why It Matters |
|---|---|
| 3D part drawing | Used for mold structure review, parting line, cavity, core, sliders and ejection |
| 2D drawing | Shows tolerances, critical dimensions and assembly requirements |
| Plastic material | Affects shrinkage, flow, steel selection, cooling and molding conditions |
| Part dimensions | Helps estimate mold size and machine size |
| Part weight | Used for shot size, cycle time and material calculation |
| Annual quantity | Helps determine cavity number and mold life requirement |
| Surface finish | Affects polishing, texture, steel selection and cost |
| Required mold life | Helps determine mold steel and standard components |
| Injection molding machine | Confirms mold size, tie-bar space, opening stroke and ejection compatibility |
| Destination country | Affects export packing, documents, electrical standard and shipping planning |
1. Product Drawing: 3D and 2D Files
The most useful file for mold quotation is a complete 3D model.
Common file formats include:
- STEP
- STP
- IGS
- IGES
- X_T
- SLDPRT
- CATPart
The 3D file helps the mold supplier review:
- Product geometry
- Parting line direction
- Undercuts
- Draft angles
- Wall thickness
- Rib structure
- Gate location options
- Slider or lifter requirements
- Ejection method
However, a 3D file is not enough for every project.
A 2D drawing is also important because it may include:
- Critical dimensions
- Tolerances
- Assembly requirements
- Surface finish notes
- Material specification
- Color requirement
- Marking requirement
- Inspection requirements
- Customer drawing revision
If the product is still in early design, the buyer should clearly say that the drawing is not final. This helps the mold supplier avoid treating the design as approved production data.
2. Plastic Material and Resin Grade
Plastic material strongly affects mold design.
Different materials have different:
- Shrinkage rates
- Flow behavior
- Cooling requirements
- Mold temperature requirements
- Wear behavior
- Corrosion risk
- Surface appearance
- Processing temperature
For example, PP, ABS, PC/ABS, PA and HDPE may all require different mold considerations.
If the material contains glass fiber, mineral filler, flame retardant or other additives, this should be clearly stated.
For high-wear materials, the mold may need:
- Hardened inserts
- Better wear-resistant steel
- Surface treatment
- Gate area protection
- Special maintenance planning
Buyers should not only write “plastic” or “PP” when requesting a quotation.
A better format is:
Material: PP
Grade: Customer to confirm
Filler: No glass fiber
Color: Black
Application: Automotive interior cover
3. Part Dimensions and Part Weight
Part dimensions help estimate mold size and machine size.
The buyer should provide:
- Part length
- Part width
- Part height
- Approximate part weight
- Wall thickness range
If the part weight is unknown, the mold supplier can estimate it from the 3D file, but the final value should be confirmed before machine selection and production planning.
Part weight is also important for:
- Shot size calculation
- Material consumption
- Cooling time
- Cycle time estimate
- Production cost estimate
- Packaging calculation
For multi-cavity molds, total shot weight should include all cavities and the runner system.
4. Annual Production Quantity
Annual production quantity is one of the most important factors in mold specification.
A mold for 20,000 parts per year and a mold for 1,000,000 parts per year should not always use the same structure, steel or cavity number.
Annual quantity affects:
- Number of cavities
- Mold steel selection
- Runner system
- Mold life target
- Automation requirements
- Cooling design
- Spare-part plan
- Production machine selection
For low-volume production, a simpler mold structure may be more economical.
For high-volume production, a higher initial mold investment may reduce long-term unit cost.
Buyers should provide a realistic annual quantity instead of only saying “large quantity” or “mass production.”
5. Number of Cavities
The number of cavities affects mold size, mold cost, cycle time, output and machine requirement.
A single-cavity mold is usually simpler and less expensive.
A multi-cavity mold can improve output, but it may require:
- Larger mold base
- Better runner balance
- Higher clamping force
- Larger shot capacity
- More accurate machining
- More complicated cooling
- More consistent ejection
The correct cavity number depends on:
- Annual production quantity
- Part size
- Part weight
- Resin flow
- Required cycle time
- Injection machine size
- Budget
- Mold life requirement
If the buyer does not know the cavity number, it is better to provide production target information and ask the mold supplier to recommend a practical solution.
6. Surface Finish and Appearance Requirements
Surface finish can significantly affect mold cost.
A technical part hidden inside a machine does not require the same mold finish as a visible automotive trim or home appliance cover.
Buyers should confirm whether the part requires:
- High gloss
- Matte texture
- Polished surface
- EDM texture
- Chemical texture
- Painted surface
- Transparent surface
- Grain pattern
- Logo or marking
- Cosmetic inspection
Visible parts may require better mold steel, more polishing work and stricter surface protection during mold manufacturing.
For automotive, home appliance and electrical appearance parts, cosmetic zones should be marked on the drawing.
7. Tolerance and Assembly Requirements
Some plastic parts only need general dimensional control.
Other parts must fit with metal parts, clips, seals, screws, motors, sensors or other plastic components.
The buyer should identify:
- Critical dimensions
- Assembly holes
- Snap-fit areas
- Sealing surfaces
- Screw bosses
- Clip positions
- Warpage-sensitive areas
- Flatness requirements
- Gap and flush requirements
Tight tolerance increases the need for:
- Better mold design
- More accurate machining
- Mold flow review
- Controlled cooling
- Stable injection molding conditions
- More trial adjustment
If the part is used in an assembly, it is helpful to provide the mating part drawing or assembly drawing.
8. Mold Life Requirement
Mold life should be discussed before quotation.
Common mold life planning ranges may include:
- Prototype or trial mold
- Low-volume production mold
- Medium-volume production mold
- High-volume production mold
- Long-life production mold
Mold life affects:
- Mold steel
- Insert design
- Wear plate design
- Surface treatment
- Standard components
- Hot runner selection
- Maintenance plan
- Spare parts
A buyer should avoid asking only for “best price” without explaining mold life.
A low-cost mold may be suitable for trial production but not suitable for a long-term production program.
9. Injection Molding Machine Information
If the buyer already has an injection molding machine, the machine data should be sent to the mold supplier.
Important machine information includes:
- Machine brand
- Machine model
- Clamping force
- Tie-bar spacing
- Platen size
- Minimum and maximum mold height
- Opening stroke
- Maximum daylight
- Ejector stroke
- Ejector force
- Ejector rod positions
- Locating ring diameter
- Nozzle radius
- Screw diameter
- Shot capacity
- Core-pull circuits
A mold can be well designed but still fail to fit the customer’s machine if this information is not checked.
This is especially important for large automotive parts, deep products, multi-cavity molds and molds requiring hydraulic core pulls.
10. Runner System: Hot Runner or Cold Runner
The runner system affects mold cost, material waste, cycle time and part quality.
A cold runner mold usually has a lower initial cost, but it may generate runner waste.
A hot runner mold has a higher initial cost, but it can reduce runner waste and support more efficient production for suitable parts.
Hot runner selection depends on:
- Material
- Part size
- Number of cavities
- Gate type
- Appearance requirement
- Production volume
- Maintenance capability
- Budget
For high-volume production, a hot runner system may reduce long-term part cost.
For low-volume or simple parts, a cold runner may be more practical.
11. Special Mold Functions
Some products require additional mold mechanisms.
Examples include:
- Sliders
- Lifters
- Hydraulic core pulls
- Unscrewing mechanisms
- Collapsible cores
- Two-shot molding
- Overmolding
- Insert molding
- Gas-assisted molding
- Valve gates
- In-mold labeling
- Automatic part removal
These functions affect mold cost, machine compatibility and lead time.
The buyer should clearly mention any special function requirement before the mold quotation is finalized.
12. Export Mold Standard and Documentation
For export molds, buyers may request additional documentation.
Common requirements include:
- Mold general assembly drawing
- Mold spare parts list
- Steel certificate
- Hot runner diagram
- Cooling diagram
- Electrical diagram
- Mold trial report
- Sample inspection report
- Mold maintenance guide
- Packing photos
- Wooden case packing
- Shipping documents
If the buyer has a company mold standard, it should be sent before quotation.
Different mold standards may require different components, design details and documentation.
Copyable Injection Mold RFQ Checklist
Buyers can copy the following checklist and send it together with the inquiry.
| Item | Buyer Information |
| Product name | |
| Product application | |
| 3D drawing available? | Yes / No |
| 2D drawing available? | Yes / No |
| Drawing file format | STEP / STP / IGS / X_T / PDF / DWG |
| Plastic material | |
| Resin grade | |
| Filler or additive | |
| Part dimensions | |
| Part weight | |
| Wall thickness | |
| Annual production quantity | |
| Required cavity number | |
| Target cycle time | |
| Surface finish | |
| Texture requirement | |
| Color requirement | |
| Tolerance requirement | |
| Assembly requirement | |
| Mold life target | |
| Runner system | Hot runner / Cold runner / Supplier recommendation |
| Preferred hot runner brand | |
| Mold steel requirement | |
| Injection machine available? | Yes / No |
| Machine brand and model | |
| Tie-bar spacing | |
| Mold height range | |
| Opening stroke | |
| Ejector stroke and layout | |
| Core-pull requirement | |
| Automation requirement | |
| Destination country | |
| Required delivery time | |
| Special mold standard | |
| Files attached |
Common Mistakes When Requesting a Mold Quote
Mistake 1: Sending Only a Product Photo
A photo can help understand the product, but it cannot provide accurate dimensions, wall thickness, undercuts or tolerances.
Mistake 2: Not Confirming the Plastic Material
Material affects shrinkage, steel selection, cooling, gate design and process conditions.
Mistake 3: Ignoring Annual Quantity
Without annual quantity, the supplier cannot properly recommend cavity number, runner system or mold life.
Mistake 4: Forgetting the Injection Machine
The mold must match the machine’s tie-bar spacing, opening stroke, mold thickness range and ejection system.
Mistake 5: Comparing Mold Prices Without Comparing Specifications
Two suppliers may quote very different prices because they use different steel, cavity numbers, runner systems, components and mold life assumptions.
Mistake 6: Asking for the Lowest Mold Price Only
The lowest initial mold price may lead to higher maintenance cost, unstable production or shorter mold life.
How Mingyu Mold Reviews a Mold Inquiry
When Mingyu Mold receives a new injection mold inquiry, the project is usually reviewed from the following points:
- Product design feasibility
- Plastic material and shrinkage
- Parting line and gate options
- Slider, lifter and ejection requirements
- Mold size and machine compatibility
- Cavity number and production target
- Mold steel and life requirement
- Surface finish and appearance requirement
- Cooling and cycle time consideration
- Export packing and project documentation
If important information is missing, we may request additional details before preparing a final quotation.
This helps avoid inaccurate pricing and reduces engineering changes after the project starts.
Frequently Asked Questions
Can I request a mold quotation without a 3D drawing?
Yes, but the quotation may only be preliminary. A product sample, photo and basic dimensions can help with early discussion, but a reliable mold quotation usually requires complete 3D and 2D drawings.
What file format is best for mold quotation?
STEP, STP, IGS, IGES and X_T are commonly used for 3D mold quotation review. PDF or DWG files are useful for 2D dimensions, tolerances and notes.
Why does the mold supplier need the plastic material?
Plastic material determines shrinkage, flow behavior, cooling requirement, steel selection and mold design details. Different resins may require different mold structures.
Do I need to decide the number of cavities before requesting a quotation?
Not always. If you provide annual production quantity, target cycle time and machine information, the mold supplier can recommend a practical cavity number.
Why does the mold supplier ask for my injection molding machine model?
The mold must fit the machine’s tie-bar spacing, mold height range, opening stroke, ejector layout, locating ring and nozzle dimensions.
Can one mold quotation include several options?
Yes. For example, the supplier may quote one option for cold runner and another option for hot runner, or one option for single cavity and another for multi-cavity production.
Why are mold quotations from different suppliers so different?
The difference may come from mold steel, cavity number, hot runner system, mold base standard, machining quality, mold life, inspection standard and project support scope.
What should I send if my product design is not final?
You can send the current drawing and clearly mark it as a preliminary design. The supplier can provide DFM comments and a rough quotation, but the final price should be confirmed after the design is frozen.
Conclusion
A good injection mold quotation begins with a complete RFQ package.
The more clearly the buyer provides product drawings, material, production quantity, mold life, surface requirements and machine information, the more accurately the mold supplier can evaluate the project.
For custom plastic injection molds, price should not be evaluated alone.
Buyers should compare mold structure, steel, cavity number, runner system, machine compatibility, trial plan, documentation and long-term production requirements.
Preparing the right information before requesting a quotation can save time, reduce risk and help the project move faster from concept to production.
