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The developing steps for a Fiberglass Project to become reality.

Most people have heard about fiberglass products and maybe even have researched enough to know that fiberglass can provide weight reduction over other products like metals, concrete and even wooden products, but they don't understand the process required to get their project produced. Below we will try to explain the basic steps required from start to finish with a fiberglass product.

Fiberglass Project Review and Production Process

Review the Fiberglass Project Design

Each new product that Arrowhead works with requires a review of the current design and the products requirements. This review process allows us to determine the manufacturability of the product and also offer suggestions to our customers that may make the product more economical and effectively.

Is the current design manufacturable with fiberglass processes?
  • Size - The size of the finished part is discussed
  • Draft Angles - 3° or greater is preferred
  • Radii - Sharp corners can hinder manufacturability
  • Wall Thickness - The thickness of the finished part is determined
  • Die locks - Does your part contain features that will require multi-piece molds?
What type of finish is required for the product?
  • Uncoated exposed resin/ glass molded surface
  • Sandable gelcoat surface for customer painting
  • Finished gelcoat industrial quality
  • Finished gelcoat Class A automotive finish
  • Post-molded painted finish
What type of fiberglass matrix and resin will be required?
  • Determine the type of resin required for project
    • General Purpose
    • Chemical Resistance
    • Fire Retardant
    • Heat Stability
    • Impact Resistance
    • UV Stability
  • Determine the fiberglass requirements
    • Glass to resin Ratio (usually 30% glass : 70% resin)
    • Fiber weave - chop strand, woven mat and bi-directional mat
    • Fiber makeup - Standard E glass, arymid fiber, carbon fiber
  • Finished gelcoat industrial quality
  • Finished gelcoat Class A automotive finish
  • Post-molded painted finish
Are secondary fabrication processes required?
Inserts and reinforcements
  • Stiffening Materials - Core mats, foam cores, balsa cores, ridged wooden cores, metal plates, engineered extrusions
  • Brackets - Hinges, threaded inserts, latches, mounts, bumpers
What type of "B" surface requirements are there?
  • Rough open glass/ resin surface (burr free)
  • Pigmented Resin
  • Hot Coated Fiberglass
  • Smooth Smooth Finish (Requires RTM Process)

 

Determine Fiberglass Molding Requirements

After the project design has been reviewed and the product designs are finalized Arrowhead will work with you to determine the types of molds, fixtures and patterns that will be required for production of your project.

What type of "B" Surface requirements were determined?
  • Rough Backside
    • One-off fabricated part
    • Open molded fiberglass part, typical volume 250 part per year per mold
  • Smooth Backside
    • RTM Lite (light weight composite molds) typical volume 2000 parts per year per mold
    • Conventional RTM (machine matched metal molds) typical volume 2750 parts per year per mold
    • CCBM molding (smooth but porous surface machined metal molds) typical volume 6000 parts per year per mold
    • Cold Molded (smooth but porous surface machined metal molds) typical volume 6000 part per year per mold
    • SMC - typical volume 12000 parts per year per mold
What type of geometry does the part consist of?
  • No die locks single cavity mold works with any above listed molding method
  • Die Locked
    • Open molded with parting flanges
    • CCBM with minor die locks
    • Other molding methods but may require experimenting and more costs

 

Temporary Pattern for Fabricating Molds

 

Starting with an existing part...
  • Part must be rigidized or reinforced to maintain shape and dimensional accuracy
  • Demolding flanges added
  • Additional thickness added to account for shrinkage (sheet wax or similar process)
  • Runout must be added to the part to allow for trimming
Starting with 3D model... (Preferred Method)
  • Shrink is added to CAD model
  • Run out and flanges added to the model as needed
  • The modified 3D CAD model is used to CNC cut the temporary pattern
Process for Finishing the Temporary Pattern
  • The pattern is sealed to prevent absorbtion of moisture and help eliminate contamination
  • Top coated and surface detailed to finish requirements
  • Release agents are applied

 

Fabricating Molds for Manufacturing

 

Open-molding Fiberglass Mold Fabrication Process
  • Tooling gel coat applied over prepped pattern
  • Backup gel coat is applied
  • 1 layer hand laid chop strand mat applied
  • 2 additional layers of non-shrink chop applied allowing curing between layers
  • Reinforcements attached and encapsulated
  • Outer surface sealed with hot coat and labeled with identifying numbers
  • Demold from temporary pattern
  • Build first article part or FRP master if additional molds are required
Closed-molding Fiberglass Mold Fabrication Process
  • Tooling gel coat applied over prepped pattern
  • Backup gel coat applied
  • One layer chopped strand fiberglass mat applied
  • Two additional layers of non-shrink chop applied (allowing curing between layers)
  • Reinforcements attached and encapsulated
  • Outer surface sealed with hot coat and labeled with identifying number
  • Demold from temporary pattern
  • Apply pre engineered sheet wax to mold cavity to simulate finished part thinkness
  • Build in the sheet wax channels for vacuum seals and resin pathways
  • Mount infection ports and vacuum ports
  • Counter Mold Production
    • RTM Lite - Gelcoat engineered wax simulation
    • Hand layup one layer of chopstrand fiberglass mat
    • Build up chop and reinforce as needed
    • CCBM - coat engineered wax with silicone material

 

Fabricating Production Parts

 

Prototype Part for First Part Approval

Arrowhead will produce the prototype part according to our customer's design, specifications and requirements.

Prototype part is sent to customer for first part approval.

Build Required Fixturing and CNC Programming (As Required)
  • CNC Fiberglass Part Trimming
    • Construct Router Nest for Part
    • Setup Program for CNC Router
  • Hand Trimming
    • Hand Router Guide
    • Scribe Production Fixture
    • Gring Off Flanges
Running Production Parts
  • After all fixturing and first part approval are completed Arrowhead begins running full production of the parts on order.
  • Open Molded Parts
    • Gel-coat is applied to the mold
    • Fiberglass and resin is applied to the mold as required
    • Core material is installed (if required)
    • Additional layers of fiberglass and resin are applied as needed
    • Part is pulled from the mold and trimmed according to prints or customer requirements
    • Part is buffed and detailed as needed
    • Fiberglass part goes through final inspection process and prepared for shipping
  • Closed Molded Parts
    • Gel-coat is applied to the mold (if required)
    • Fiberglass mat and core material is placed into mold
    • Counter-mold is mounted into place
    • Resin and catalyst are injected into the mold
    • Part is pulled from the mold and trimmed according to prints or customer requirements
    • Part is buffed and detailed as needed
    • Fiberglass part goes through final inspection process and prepared for shipping

     

 


Arrowhead Plastic Engineering, Inc. provides this information as a very basic guidelines for the steps that you will need to get your fiberglass product design from the design phase to the final product. Each project may present specialized situation and product development that are not listed above.



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