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GMC Sierra Denali AT4 CarbonPro pickup box

News International-French

31 Oct 2019

The CarbonPro box is the world’s first use of carbon fiber reinforced thermoplastics for structural parts in a high production volume vehicle. The material, box design, and related production and manufacturing process innovations represent a collaborative effort between CSP,  its parent company Teijin, and General Motors.

GMC Sierra Denali AT4 CarbonPro Pickup Box

GMC Sierra Denali AT4 CarbonPro Pickup Box

Steven Rooney, CEO, Continental Structural Plastics:

Steven Rooney, CEO, Continental Structural Plastics


"The CarbonPro pickup box is the industry’s first use of carbon fiber for a pickup truck box. It is made from Teijin’s Sereebo carbon fiber reinforced thermoplastic (CFRTP) material. The CarbonPro pickup box was jointly developed by Teijin and GM for the GMC Sierra Denali 1500 and GMC Sierra AT4 1500. Specifically, the pickup box’s inner headboard, side and floor panels are made with Sereebo.

Following production startup in June, GMC Sierra CarbonPro Editions for both vehicles began appearing at select GMC dealerships in the U.S. this summer. The CarbonPro panels are being produced at Continental Structural Plastics’ Huntington, Indiana, manufacturing facility.

Sereebo used for CarbonPro contains randomly orientated, isotropic carbon fiber in a polyamide matrix resin. Manufactured using with the world’s first mass-production technology for CFRTP, the molding time for Sereebo is approximately one minute, which is significantly shorter than the molding time for conventional carbon fiber reinforced thermoset plastics (CFRP). Compared to steel, CarbonPro is 40 percent lighter, offers 10 times greater impact resistance, is more corrosion-resistant, and is even more readily recyclable. Finally, because of its material characteristics, Sereebo offers extended design flexibility and freedom, which allowed GM engineers to mold in many of the unique features of the CarbonPro box."

The Sierra’s CarbonPro carbon fiber box replaces the standard steel inner panels and floor with a lightweight, purpose-designed carbon fiber composite called Carbon-Fiber Reinforced Plastic (CFRP).

GMC Sierra Denali AT4 CarbonPro Pickup Box

GMC Sierra Denali AT4 CarbonPro Pickup Box exploded view

Discover how a classical Pickup Box is made?
The video hereunder described the global process to realize a pickup box made with composite material. For the GMC Sierra Denali AT4 CarbonPro pickup box, please note that the fabrication process is different as: the material used is not the same, the parts assembled are not the same and as there is no need for painting.

How a Pickup Box is made from Composites

Step 1 : Preparation of the compounding materials
Pick up box production begins with the compounding of the raw materials in one of CSP composite compounding facility.

To begin production of the advanced composites, raw materials are delivered to CSP compounding facilities by rail or tanker truck. Once inside the materials are mixed and blended according to a number of customized formulations based on specific customer or application needs. To ensure quality and product consistency CSP in house chemical labs continually test the materials for viscosity and other significant properties.

Advanced composites used for pickup boxes are most commonly made from vinyl ester resin with glass fiber reinforcements, which is choped and randomly oriented. Additional ingredientq include catalysts to cure, termoplastic additiveq to reduce shrinking, fillers and mold release agents.The compounding process begins with a roll of plastic film fed through the transport system. The machine then deposit a layer of resin compounded on the film then the chopped glass cut from standed rovings is dropped on the resin in random orientation.

The upper layer of resin film is placed on the lower layer to form the composite.

The upper layer of resin film is placed on the lower layer to form the composite.

In the next step the upper layer of resin film is placed on the lower layer to form the composite. The material then, goes through a compaction roller system where any excess air trapped between layers is removed. The material is needed to wet the glass fibers with the resin and it is pressed to the desired thickness. The composite is then packaged and shipping festoon and taken to the maturation room where it will be stored for one to three days. Once the optimal viscosity is reached, it is shipped off to one of our manufacturing facilities to be molded into components including Class A body panels pickup truck boxes, or any number of under hood or underbody vehicle parts.

Step 2 : Material cutting and positioning
Advanced composites arrive at the plants in shipping festoons and are stored in a temperature controlled environment before use. Material are selected according to first-in, first-out best pratices by trained operators for delivery to the press. Upon delivery to the press, the material is attached to a slitter which pulls material from the festoons and winds up the protective plastic film on mandrels.

Upon delivery to the press, the material is attached to a slitter which pulls material from the festoons and winds up the protective plastic film on mandrels.

Upon delivery to the press, the material is attached to a slitter which pulls material from the festoons and winds up the protective plastic film on mandrels.
 

The slitter indexes the material to pre-programmed lengths or charges as determined by process engineering. The press operator follows work instructions to weigh and prepare each charge and the geometrically arrange it on an automatic press loader.

Step 3 : Vaccum molding process
Each part is then molded using CSP's patented vaccum molding process.The press loader delivers the prepared charge to the mold and places the charge precisely on the press to ensure uniform consistent quality boxes. The molding time is approximately one minute, which is shorter than the molding time for conventional carbon fiber reinforced thermoset plastics (CFRP).

The press loader delivering the prepared charge to the mold and placing the charge precisely on the press to ensure uniform consistent quality boxes

The press loader delivering the prepared charge to the mold and placing the charge precisely on the press to ensure uniform consistent quality boxes

Step 4: Drilling - Cleaning - Painting
After the molded box or box is ejected from the mold, it is deflashed prior to a series or drilling operations, cleaning and painting.

In the case of multi piece boxes, bounding of the various pieces would take place at this point in the process. The various steps that take place during the finishing process are determined by part design and customers specifications but can included additional drilling and hardware attachment storage box and tailgate assembly or shipping preparation.

Once the pickup box is demolded drilling, cleaning, assembling and painting steps can start

Once the pickup box is demolded drilling, cleaning, assembling and painting steps can start

In the case of Sereebo material, we can use a wide variety of well-know joining methods. Certain types of adhesives work well, but ultrasonic welding is more cost-effective and efficient. Continuous, ultrasonic welding is a simple, flexible process. Takt time is between 3 to 5 seconds for oscillation and cooling. Similar to conventional welding for steel parts. Peers stoppers like rivets or ultrasonic staking with molded boss or resin rivets are also possible. Combinaison of welding and staking provided significant joint strangth, allows for part design flexibility.

Sereebo™

Joining process from 3m44s

Step 5: Quality control
In addition to daily Coordinate Measuring Machine (CMM) measuring of producition boxes, it is important to note that each step of the manufacturing process: the prior step is quality check to ensure non-conforming parts are made. Before the box is placed on the shipping rack it goes through one final inspection, to ensure all processes including drilling, bonding and painting are completed according to the customers specifications.

Coordinate Measuring Machine (CMM) in action

Coordinate Measuring Machine (CMM) in action

Step 6: Final part
The pickup boxes are then placed into racks, load on the trucks and shipped to the OEM's facility for final assembly.

 

GMC Sierra Denali AT4 CarbonPro pickup box

CarbonPro box is the world’s first use of carbon fiber reinforced thermoplastics

Key benefits of the CarbonPro bed include:

  • Strength, durability and scratch resistance: The carbon fiber composite material provides the most scratch, dent and corrosion-resistant pickup bed in the industry.
  • Corrosion-resistance: Carbon fiber composite naturally resists corrosion, helping the bed withstand weathering and maintain a premium appearance over the life of the truck.
  • Reduced weight: The CarbonPro bed weighs 25 percent less than a traditional steel bed, removing roughly 60 pounds of vehicle mass. Its grained surface also negates the need for bed liners, potentially saving further vehicle mass.
  • More volume: The CarbonPro bed design enables best-in-class cargo volume, increasing the already class-leading volume of the Sierra’s roll-formed steel bed by 1 cubic foot.
  • More functionality: The CarbonPro bed features indentations specifically designed for tires of dirt and street bikes. Two additional tie-down locations are installed at the front of the bed.

GMC Sierra Denali AT4 CarbonPro pickup box


What strategies can be put in place to control the environmental cost of composite materials and their end-of-life?

Steven Rooney, CEO, Continental Structural Plastics:

Steven Rooney, CEO, Continental Structural Plastics

"The strategy varies based on the material selected. For example, Teijin’s Sereebo material is recyclable. In the process to make the CarbonPro box, offal is grinded and recycled to mold additional components used for the pickup box. For thermoset materials, CSP is currently exploring a number of recycling processes through which the glass or carbon fibers and resins can be recaptured. We are doing this on a small scale in the laboratory now, while simultaneously developing methods to do the same thing on a larger scale."

 

Rigorous validation testing
The CarbonPro bed was rigorously developed to help ensure long-term pickup bed durability and functionality.
Examples of the validation testing include:

  • Drop tests: Large and heavy loads were repeatedly dropped on the CarbonPro bed to replicate extreme use scenarios. Testing included dropping cinder blocks, 1800-pound loads of gravel and 450-pound water-filled steel drums from varying heights.
  • Corrosion test: CarbonPro was subjected to corrosion testing but carbon fiber composite is naturally resistant to corrosion.
  • Snowmobile test: A snowmobile with metal studs on the track was driven into the bed and accelerated at full throttle with a 250-pound rider on board with only minimal scratching evident on the bed.
  • Extreme temperature testing: Validation work was performed in Yuma, Arizona, and Kapuskasing, Ontario, to help ensure CarbonPro holds up in unforgiving environments.
  • Generator test: High heat exposure involved aiming the exhaust from a portable generator directly at the corner of the bed to ensure heat and vibration would not degrade the bed.

    Form meets function
    The CarbonPro bed offers best-in-class cargo volume thanks to its sidewalls being pushed out farther, made possible by the formability of carbon fiber composite that allows molding deep and complex shapes with variable thicknesses. Like the steel bed, the CarbonPro bed provides the ability to slide a 2-inch by 6-inch wooden divider into pockets in the bed wall for cargo organization and separation.

    Purposefully grained corrugation optimizes traction and cleanup, with more aggressive graining at the tops of the corrugation to help increase traction in wet weather and a smoother grain at the bottoms of the corrugation for easy dirt and debris removal.

    The carbon fiber composite bed does not need to be painted, since the composite material creates a premium surface and is UV stable.  

    GMC Sierra Denali AT4 CarbonPro pickup box

    The interview of Steven Rooney, CEO Continental Structural Plastics, is extracted from the JEC Composites Magazine N°131.

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