By Serena Zhang | 09 July 2025 | 0 Comments
How to Use Epoxy Resin? (from raw materials to precise models for beginners）
How to Use Epoxy Resin? (Analysis of the complete manufacturing process of epoxy resin, carbon fiber and glass fiber composite materials from raw materials to precise models for beginners)
Epoxy resin, also known as fiberglass, is very hard and is often used in a variety of model manufacturing. For example, high-precision military parts or beautiful decorative sculptures in shopping malls. Inject it into the foam model and wait for it to solidify to create a variety of shapes.
Epoxy resin, carbon fiber, glass fiber, these advanced composite materials are being increasingly used in our lives. But do you know their similarities and differences? How to use epoxy resin?Do you know how it is applied to various industries? Next, I will introduce the complete manufacturing process and case analysis from raw materials to precision models in detail with epoxy resin as the main focus.
The advantages of epoxy resin applied in molds of Car Shells, Yacht Hulls, and Wind Turbine Blades:
Why choose epoxy resin for large molds?
1. Cost saving
Steel mold: like making a tank, expensive materials, slow processing, very expensive
Epoxy mold: equivalent to "fiberglass mold", the cost is directly cut by 70% (like buying a car vs. buying a bicycle)
2. Fast to make, easy to modify
Traditional steel mold: It takes half a year to make a mold
Epoxy mold:
① First carve out the prototype with foam or wood
② Paste fiberglass cloth + epoxy resin like pasting a paper box
③ Vacuum and press → Put it in the oven for a few days → Finished!
The whole process takes only 2-3 weeks, and changing the size is like repairing a tire, just a partial repair is enough
3. Very light weight
10-meter-long hull mold:
- Steel mold ≈ 10 elephants (can only be moved by a crane)
- Epoxy mold ≈ 2 cows (can be carried by a few people)
4. More advantages in application
Case 1: Yacht building
Traditional: Steel mold costs 5 million and takes 1 year
Epoxy mold: Cost 800,000 and takes 3 months → The shipyard saves money to buy two more production lines
Case 2: Car bumper
Use epoxy mold to press out 100,000 plastic parts → The surface is as smooth as a mobile phone screen, and even the leather texture can be copied
Special skills:
✓ Resistant to high temperatures of 200℃ (enough to cook steak)
✓ Thermal expansion and contraction are 10 times smaller than metal → The size of the parts produced is more accurate
Epoxy Resin and Carbon Fiber:
Most advanced composite material applications in CNC Mold machines
Scientific analysis of composite materials: When epoxy resin meets reinforced fiber
Epoxy resin, as the key matrix of composite materials, has become the darling of high-end fields such as aerospace and automobiles due to its high strength, high modulus, high temperature resistance and chemical corrosion resistance. However, pure epoxy resin has defects such as high brittleness and poor bending performance, which need to be compensated by reinforcing fibers-this is the stage for carbon fiber and glass fiber to show their prowess.
The density of carbon fiber is only 1.8g/cm³, but its strength is as high as 3500MPa (theoretical value, actual about 700-1400MPa). Its ultra-high specific strength has become the core advantage of replacing metal. Although glass fiber has a slightly higher density (2.5g/cm³), it is lower in cost and has unique insulation properties. When they are combined with epoxy resin, they form a composite material with a leap in performance.
How to use epoxy resin making models?
(Steps for making different models with epoxy resin
Covering the key technologies of the whole process from material preparation to post-processing, combining engineering practice parameters with innovative processes:)
►Material preparation stage
1. Epoxy resin system selection
| Resin type | Applicable scenarios | Characteristic parameters |
|----------------|---------------------------|--------------------------|
| Bisphenol A type (E-51) | Precision structural parts | Viscosity 650mPa·s (25℃), Tg=120℃ |
| Alicyclic (ERL-4221) | Transparent optical parts | Transmittance>92%, Yellowing resistance index 8 |
| Modified toughness (AG-80) | High impact resistant parts | Elongation at break 18%, K₁c=1.8MPa·√m |
2. Add curing agent
3. Mold pretreatment
The model that needs to be prepared in advance is generally made of foam or silicone. Here we need to use a professional model engraving machine to engrave and make the model. The most commonly used ones are RHINO series 4-axis and 5-axis mold CNC Router, which are used for large-scale high-precision mold production.
4.Demolding system construction:
Base layer: PMR polyester release film (thickness 0.1mm)
Middle layer: semi-permanent demoulding wax (3 times polishing)
Surface layer: PTFE spray (film thickness 8μm)
5.Positioning reference setting:
Install Φ3mm positioning pin (tolerance H7/g6)
Set ejection slope ≥3°
►Mixing and pouring process
1. Precise mixing control
2. Advanced pouring technology
Gradient density pouring:
Vacuum-assisted pouring:
Injection port pressure: 0.15MPa
Runner design: Width ≥ 5mm, taper 15°
Exhaust timing: Open the vacuum valve after 90% of the material is filled
►Curing dynamics control
►Demolding and finishing
1. Non-destructive demolding technology
2. Air pressure ejection system:
Step pressure: 0.2MPa→0.5MPa→0.8MPa
Ejector layout spacing ≤50mm
Freezing demolding method:
-30℃ liquid nitrogen spray
Thermal expansion coefficient difference: Δα=45×10⁻⁶/K
3.CNC finishing parameters
The mold engraving machine is needed again. Our professional high-precision model engraving machine will polish and trim the surfaces of epoxy resin, glass fiber, carbon fiber, etc. after demolding.
Key points for preventing brittle cracking:
Cutting temperature < resin Tg-20℃
Feed direction parallel to fiber orientation
►Surface strengthening treatment
Functional coating preparation
Wear-resistant coating:
Base layer: epoxy/carbon nanotube (0.3%wt)
Surface layer: UV-cured polyurethane acrylate
Thickness: 20±2μm, hardness 3H
Metallization treatment:
Chemical nickel plating: Ni-P layer thickness 8μm
Bond strength: ASTM D3359 5B grade
Application cases:
►Satellite reflector mold
Material production:
Resin: CYCOM 985 (space-grade epoxy)
Layer: carbon fiber/glass fiber hybrid (CTE=0.8×10⁻⁶/K)
Ultra-precision machining:
Equipment: Moore Nanotech 350FG
Accuracy: surface accuracy λ/20@632.8nm
Roughness: Ra 2.8nm
Temperature stability treatment:
Cycling conditions: -80℃~+120℃, 50 cycles
Deformation: ≤0.25μm/100mm
►The whole process of drone fuselage manufacturing
1. Mold processing
Material: Invar (thermal expansion coefficient 1.6×10⁻⁶/℃)
Engraving accuracy: ±5μm/m
2. Carbon fiber laying
12 layers of T700SC are laid using an automatic tape laying machine
Local reinforcement: Kevlar honeycomb core (density 48kg/m³) is inserted in key parts
3. Intelligent curing
Built-in FBG fiber sensor monitors strain in real time
Dynamically adjusts pressure curve to avoid deformation
4. Finishing stage
Water-guided laser opening (servo mounting hole)
Ultrasonic vibration processing antenna slot (surface roughness Ra1.6μm)
5. Functionalization
Surface magnetron sputtering ITO conductive film (square resistance 10Ω/□)
Laser engraving FSS frequency selective surface (bandpass characteristic 2.4GHz)
Key to precision control: temperature fluctuation of the whole process ≤±0.5℃, humidity controlled at 45%RH, final product weight deviation <0.8%, aerodynamic shape error <0.05mm
Carbon fiber composite material model making (aerospace grade structural parts)
▶ Core technology:
Layer design → Autoclave molding → Laser cutting → Five-axis engraving → Non-destructive testing
1. Prepreg layering technology
Material: T800SC/epoxy prepreg (single layer thickness 0.125mm)
2. Autoclave molding
Temperature curve: 110℃(60min)→180℃(120min)
Pressure: 0.6MPa step pressurization
Vacuum degree: ≤50Pa
Fiberglass composite material model making (lightweight automotive parts)
▶ Rapid prototyping process:
3D printing master mold → fiberglass winding → RTM injection molding → CNC cutting → edge finishing
1.3D printing master mold: First, you need to use a 3D printer or related equipment to make the original model of the automotive parts. Here you can choose a 3D printer or a 5-axis engraving machine, KUKA robotic arm to make it
2. Fiberglass Filament Winding: (Fiberglass Filament Winding) is a continuous fiber reinforced composite material manufacturing process. By winding the resin-impregnated glass fiber on the model surface according to a predetermined trajectory, it forms a high-strength and lightweight structural part after curing
3.RTM injection molding: (Resin Transfer Molding) By laying a reinforced fiber preform (such as carbon fiber, glass fiber) in a closed mold, a low-viscosity resin is injected into the mold cavity under pressure to fully infiltrate the fiber, and demolding after heating and curing
4.CNC cutting: A water jet or laser cutting machine is generally used here
5. Edge finishing: A high-precision CNC 5-axis engraving machine is required to trim, grind and polish the model surface
Epoxy Resin Molds FAQ: Your Top Questions Answered
(For Automotive, Marine & Aerospace Applications)
Q1: How much can I save with epoxy molds vs. steel molds?
✅ Cost Comparison:
• Automotive bumper mold: Steel $110K → Epoxy $18K-$35K
• Boat hull mold: Steel $700K+ → Epoxy $85K-$140K
Save 60-75% on prototypes/low-volume production
Q2: What’s the maximum lifespan of epoxy resin molds?
Durability Data:
• Standard: 50,000+ cycles (plastic injection molding)
• With PTFE coating: 200,000+ cycles
• Temperature resistance: 392°F (200°C) proven
Q3: How fast can I get a large epoxy mold?
⏱️ Lead Time Breakthrough:
Total: 16 days (vs. 4-6 months for steel tooling)
Q4: Will a 10m epoxy mold warp or deform?
Precision Engineering:
• Near-zero CTE: 11x10⁻⁶/K (vs. steel 23x10⁻⁶/K)
• Carbon fiber grid reinforcement
• Accuracy: ±0.08 in/m (±2mm/10m)
Q5: When should I NOT use epoxy molds?
⚠️ Material Limitations:
• Not for:
• High-pressure die casting
• >500,000 part runs
• Textures <0.002” depth
Q6: Can epoxy molds replicate high-gloss finishes?
✨ Surface Capabilities:
• Mirror polish: Ra 0.1-0.4 μm
• Perfect texture transfer:
✔️ Carbon fiber weave
✔️ Leather grain
✔️ Wood grain
Q7: How to repair damaged epoxy molds?
Field Repair Kit:
1. Sand damaged area
2. Apply epoxy putty (e.g., Devcon Plastic Steel)
3. Cure with IR heater (30 min @ 176°F/80°C)
Cost: <$200 vs. $5K+ for steel weld repair
Q8: Where to find certified epoxy mold suppliers?
Global Sourcing Guide:
• Top regions: Germany (automotive), China (marine), USA (aerospace)
• Verify:
• ISO 9001 + AS9100 certifications
• Material test reports (Tg, flexural strength)
• Case studies >5m project length
Epoxy resin, also known as fiberglass, is very hard and is often used in a variety of model manufacturing. For example, high-precision military parts or beautiful decorative sculptures in shopping malls. Inject it into the foam model and wait for it to solidify to create a variety of shapes.
Epoxy resin, carbon fiber, glass fiber, these advanced composite materials are being increasingly used in our lives. But do you know their similarities and differences? How to use epoxy resin?Do you know how it is applied to various industries? Next, I will introduce the complete manufacturing process and case analysis from raw materials to precision models in detail with epoxy resin as the main focus.
The advantages of epoxy resin applied in molds of Car Shells, Yacht Hulls, and Wind Turbine Blades:
Why choose epoxy resin for large molds?
1. Cost saving
Steel mold: like making a tank, expensive materials, slow processing, very expensive
Epoxy mold: equivalent to "fiberglass mold", the cost is directly cut by 70% (like buying a car vs. buying a bicycle)
2. Fast to make, easy to modify
Traditional steel mold: It takes half a year to make a mold
Epoxy mold:
① First carve out the prototype with foam or wood
② Paste fiberglass cloth + epoxy resin like pasting a paper box
③ Vacuum and press → Put it in the oven for a few days → Finished!
The whole process takes only 2-3 weeks, and changing the size is like repairing a tire, just a partial repair is enough
3. Very light weight
10-meter-long hull mold:
- Steel mold ≈ 10 elephants (can only be moved by a crane)
- Epoxy mold ≈ 2 cows (can be carried by a few people)
4. More advantages in application
Case 1: Yacht building
Traditional: Steel mold costs 5 million and takes 1 year
Epoxy mold: Cost 800,000 and takes 3 months → The shipyard saves money to buy two more production lines
Case 2: Car bumper
Use epoxy mold to press out 100,000 plastic parts → The surface is as smooth as a mobile phone screen, and even the leather texture can be copied
Special skills:
✓ Resistant to high temperatures of 200℃ (enough to cook steak)
✓ Thermal expansion and contraction are 10 times smaller than metal → The size of the parts produced is more accurate
Epoxy Resin and Carbon Fiber:
Most advanced composite material applications in CNC Mold machines
Scientific analysis of composite materials: When epoxy resin meets reinforced fiber
Epoxy resin, as the key matrix of composite materials, has become the darling of high-end fields such as aerospace and automobiles due to its high strength, high modulus, high temperature resistance and chemical corrosion resistance. However, pure epoxy resin has defects such as high brittleness and poor bending performance, which need to be compensated by reinforcing fibers-this is the stage for carbon fiber and glass fiber to show their prowess.
The density of carbon fiber is only 1.8g/cm³, but its strength is as high as 3500MPa (theoretical value, actual about 700-1400MPa). Its ultra-high specific strength has become the core advantage of replacing metal. Although glass fiber has a slightly higher density (2.5g/cm³), it is lower in cost and has unique insulation properties. When they are combined with epoxy resin, they form a composite material with a leap in performance.
How to use epoxy resin making models?
(Steps for making different models with epoxy resin
Covering the key technologies of the whole process from material preparation to post-processing, combining engineering practice parameters with innovative processes:)
►Material preparation stage
1. Epoxy resin system selection
| Resin type | Applicable scenarios | Characteristic parameters |
|----------------|---------------------------|--------------------------|
| Bisphenol A type (E-51) | Precision structural parts | Viscosity 650mPa·s (25℃), Tg=120℃ |
| Alicyclic (ERL-4221) | Transparent optical parts | Transmittance>92%, Yellowing resistance index 8 |
| Modified toughness (AG-80) | High impact resistant parts | Elongation at break 18%, K₁c=1.8MPa·√m |
2. Add curing agent
3. Mold pretreatment
The model that needs to be prepared in advance is generally made of foam or silicone. Here we need to use a professional model engraving machine to engrave and make the model. The most commonly used ones are RHINO series 4-axis and 5-axis mold CNC Router, which are used for large-scale high-precision mold production.
4.Demolding system construction:
Base layer: PMR polyester release film (thickness 0.1mm)
Middle layer: semi-permanent demoulding wax (3 times polishing)
Surface layer: PTFE spray (film thickness 8μm)
5.Positioning reference setting:
Install Φ3mm positioning pin (tolerance H7/g6)
Set ejection slope ≥3°
►Mixing and pouring process
1. Precise mixing control
2. Advanced pouring technology
Gradient density pouring:
Vacuum-assisted pouring:
Injection port pressure: 0.15MPa
Runner design: Width ≥ 5mm, taper 15°
Exhaust timing: Open the vacuum valve after 90% of the material is filled
►Curing dynamics control
►Demolding and finishing
1. Non-destructive demolding technology
2. Air pressure ejection system:
Step pressure: 0.2MPa→0.5MPa→0.8MPa
Ejector layout spacing ≤50mm
Freezing demolding method:
-30℃ liquid nitrogen spray
Thermal expansion coefficient difference: Δα=45×10⁻⁶/K
3.CNC finishing parameters
The mold engraving machine is needed again. Our professional high-precision model engraving machine will polish and trim the surfaces of epoxy resin, glass fiber, carbon fiber, etc. after demolding.
| Process | tools | parameters | Cooling way |
| Roughly milling | End milling diameter 20mm tools | vc=200m/min, fz=0.1mm | Air cooling/water cooling |
| Half roughly milling | End milling diameter 15mm tools | vc=300m/min, ap=0.3mm | Air cooling/water cooling |
| Detailed milling | Pointed milling tools 15-20mm | vc=500m/min, f=0.01mm | Air cooling/water cooling |
Cutting temperature < resin Tg-20℃
Feed direction parallel to fiber orientation
►Surface strengthening treatment
Functional coating preparation
Wear-resistant coating:
Base layer: epoxy/carbon nanotube (0.3%wt)
Surface layer: UV-cured polyurethane acrylate
Thickness: 20±2μm, hardness 3H
Metallization treatment:
Chemical nickel plating: Ni-P layer thickness 8μm
Bond strength: ASTM D3359 5B grade
Application cases:
►Satellite reflector mold
Material production:
Resin: CYCOM 985 (space-grade epoxy)
Layer: carbon fiber/glass fiber hybrid (CTE=0.8×10⁻⁶/K)
Ultra-precision machining:
Equipment: Moore Nanotech 350FG
Accuracy: surface accuracy λ/20@632.8nm
Roughness: Ra 2.8nm
Temperature stability treatment:
Cycling conditions: -80℃~+120℃, 50 cycles
Deformation: ≤0.25μm/100mm
►The whole process of drone fuselage manufacturing
1. Mold processing
Material: Invar (thermal expansion coefficient 1.6×10⁻⁶/℃)
Engraving accuracy: ±5μm/m
2. Carbon fiber laying
12 layers of T700SC are laid using an automatic tape laying machine
Local reinforcement: Kevlar honeycomb core (density 48kg/m³) is inserted in key parts
3. Intelligent curing
Built-in FBG fiber sensor monitors strain in real time
Dynamically adjusts pressure curve to avoid deformation
4. Finishing stage
Water-guided laser opening (servo mounting hole)
Ultrasonic vibration processing antenna slot (surface roughness Ra1.6μm)
5. Functionalization
Surface magnetron sputtering ITO conductive film (square resistance 10Ω/□)
Laser engraving FSS frequency selective surface (bandpass characteristic 2.4GHz)
Key to precision control: temperature fluctuation of the whole process ≤±0.5℃, humidity controlled at 45%RH, final product weight deviation <0.8%, aerodynamic shape error <0.05mm
Carbon fiber composite material model making (aerospace grade structural parts)
▶ Core technology:
Layer design → Autoclave molding → Laser cutting → Five-axis engraving → Non-destructive testing
1. Prepreg layering technology
Material: T800SC/epoxy prepreg (single layer thickness 0.125mm)
2. Autoclave molding
Temperature curve: 110℃(60min)→180℃(120min)
Pressure: 0.6MPa step pressurization
Vacuum degree: ≤50Pa
Fiberglass composite material model making (lightweight automotive parts)
▶ Rapid prototyping process:
3D printing master mold → fiberglass winding → RTM injection molding → CNC cutting → edge finishing
1.3D printing master mold: First, you need to use a 3D printer or related equipment to make the original model of the automotive parts. Here you can choose a 3D printer or a 5-axis engraving machine, KUKA robotic arm to make it
2. Fiberglass Filament Winding: (Fiberglass Filament Winding) is a continuous fiber reinforced composite material manufacturing process. By winding the resin-impregnated glass fiber on the model surface according to a predetermined trajectory, it forms a high-strength and lightweight structural part after curing
3.RTM injection molding: (Resin Transfer Molding) By laying a reinforced fiber preform (such as carbon fiber, glass fiber) in a closed mold, a low-viscosity resin is injected into the mold cavity under pressure to fully infiltrate the fiber, and demolding after heating and curing
4.CNC cutting: A water jet or laser cutting machine is generally used here
5. Edge finishing: A high-precision CNC 5-axis engraving machine is required to trim, grind and polish the model surface
Epoxy Resin Molds FAQ: Your Top Questions Answered
(For Automotive, Marine & Aerospace Applications)
Q1: How much can I save with epoxy molds vs. steel molds?
✅ Cost Comparison:
• Automotive bumper mold: Steel $110K → Epoxy $18K-$35K
• Boat hull mold: Steel $700K+ → Epoxy $85K-$140K
Save 60-75% on prototypes/low-volume production
Q2: What’s the maximum lifespan of epoxy resin molds?
Durability Data:
• Standard: 50,000+ cycles (plastic injection molding)
• With PTFE coating: 200,000+ cycles
• Temperature resistance: 392°F (200°C) proven
Q3: How fast can I get a large epoxy mold?
⏱️ Lead Time Breakthrough:
Total: 16 days (vs. 4-6 months for steel tooling)
Q4: Will a 10m epoxy mold warp or deform?
Precision Engineering:
• Near-zero CTE: 11x10⁻⁶/K (vs. steel 23x10⁻⁶/K)
• Carbon fiber grid reinforcement
• Accuracy: ±0.08 in/m (±2mm/10m)
Q5: When should I NOT use epoxy molds?
⚠️ Material Limitations:
• Not for:
• High-pressure die casting
• >500,000 part runs
• Textures <0.002” depth
Q6: Can epoxy molds replicate high-gloss finishes?
✨ Surface Capabilities:
• Mirror polish: Ra 0.1-0.4 μm
• Perfect texture transfer:
✔️ Carbon fiber weave
✔️ Leather grain
✔️ Wood grain
Q7: How to repair damaged epoxy molds?
Field Repair Kit:
1. Sand damaged area
2. Apply epoxy putty (e.g., Devcon Plastic Steel)
3. Cure with IR heater (30 min @ 176°F/80°C)
Cost: <$200 vs. $5K+ for steel weld repair
Q8: Where to find certified epoxy mold suppliers?
Global Sourcing Guide:
• Top regions: Germany (automotive), China (marine), USA (aerospace)
• Verify:
• ISO 9001 + AS9100 certifications
• Material test reports (Tg, flexural strength)
• Case studies >5m project length
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