MAXComposite

What is MAXComposite?

MAXComposite is made from self-reinforced polypropylene (SRPP), a pure thermoplastic material combining two molecular weights of polypropylene with different melting points.

During production, polymer chains are stretched and aligned into individual sheets, which are stacked and heat pressed under precisely controlled temperature, time, and pressure. This causes only the lower melting point polypropylene to bond, forming a matrix that secures the unmelted fibers (thus “self-reinforced”). The result is an exceptionally strong and rigid sheet with significantly higher strength than standard polypropylene.

MAXComposite is available in 0.1-inch and 0.2-inch thicknesses with sheet sizes of 47 by 23 inches. MAXComposite is 25% lighter than polycarbonate and impervious to Loctite, making it a durable and lightweight choice for various mechanisms and builds.

How to Use

Prototyping & Test Cuts

To reduce material waste and optimize designs, it is highly recommended to prototype using similar thickness materials such as 5mm (0.2-inch) underlayment or plywood before committing to MAXComposite.

Before cutting large parts, perform:

• Small test cuts with simple shapes to dial in laser or CNC settings.

• Critical tolerance tests, such as press-fit bearing holes or shaft clearances, to ensure accuracy.

Cutting & Fabrication

Laser Cutting

CO₂ laser cutting is the most effective method for precise fabrication. Proper laser settings are essential to achieve clean cuts without excessive melting or rebonding. The laser also seals the edges, preventing delamination. A higher flow air assist is recommended for best results. Ensure adequate ventilation as moderate smoke is produced during cutting.

Recommended Laser Cutting Settings (Based on a 100W CO₂ Laser):

• 0.2-inch sheets: 90-100% power, 5-10 mm/s speed (lower-powered lasers may require slower speeds)

• 0.1-inch sheets: 90-100% power, 20-25 mm/s speed (adjust speeds accordingly for lower-powered lasers)

Manual Cutting Methods

For resizing sheets to fit laser cutter beds, conventional tools such as table saws, bandsaws, or jigsaws can be used. However, be cautious of overheating and rapid air cooling, which may cause jamming in high-speed tools.

Processing Techniques:

• Table saw / Circular saw – effective for straight cuts and resizing for laser beds

• Jigsaw – useful for intricate or curved cuts or quick edits

• Bandsaw - slightly more controlled cuts than a jigsaw, but may not remelt edges

• Edge remelt techniques – reapplying heat to edges can help prevent delamination

Fitment & Finishing

Testing & Fitment

Before cutting larger parts, test fitment for bearing presses and hardware clearance. On our laser, a 1.1-inch diameter hole results in a snug arbor press fit for a rounded hex bearing.

Finishing Techniques

Some melted plastic may accumulate on the back of cut parts. Consider which surfaces need to remain smooth and use the following techniques for cleanup:

• Sanding

• Deburring tools

• Knife trimming

Note: Keep edges slightly melted together to prevent delamination.

Drilling & Adhesion

• Drilling: Sharp drill bits work for additional holes, and hole saws or jigsaws are effective for non-precision cuts.

• Adhesion: Due to polypropylene’s low surface energy, most adhesives do not bond well. Stickers and graphics require large surface areas, and for aesthetic purposes, you can mask and paint MAXComposite using plastic primers and paints.

CNC Machining

CNC Routing Considerations

While CNC machining is possible, CO₂ laser cutting provides the best results. If CNC routing is necessary, compression bits and proper workholding are critical.

Best CNC Machining Practices:

• Use a compression bit for optimal edge quality.

• Secure material with a vacuum table or screw it into a spoil board.

• Maintain a slight melt on edges to prevent delamination.

Tested CNC Settings:

• 1/8-inch compression bit

• 18,000 RPM spindle speed

• 108 in/min feed rate (0.003 inches per tooth)

Bending MAXComposite

Heat Bending Guidelines

MAXComposite can be heat-formed best using fixturing at 230-240°F. Avoid exceeding 250-260°F + to prevent degradation. Polypropylene melts at 320°F, so staying within the recommended range ensures proper bending without compromising strength.

For best results, use a heat source such as a strip heater or heat gun, applying even heat across the bending area. Secure the part in a bending jig immediately after heating to achieve the desired shape and prevent warping.

Chemical Resistance

MAXComposite is made entirely of polypropylene blends, making it highly resistant to chemicals. It remains unaffected by:

• Threadlockers (e.g., Loctite)

• Solvents (e.g., acetone)

This chemical resistance ensures that builds using Loctite remain secure and durable, even in the most intense competitions.

Best Practices & Recommendations

General Guidelines:

• Prototype with plywood to reduce material waste.

• Test laser settings on small cuts before full-scale production.

• Ensure proper ventilation when laser cutting.

• Use proper tools to maintain material integrity.

• Remelt edges slightly after cutting to prevent delamination.

• For CNC machining, prioritize compression bits and stable workholding.

By following these best practices, MAXComposite offers exceptional strength, weight savings, and fabrication ease, making it an ideal choice for a variety of applications.