# 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 sheet in 0.1in (top) and 0.2in (bottom)

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. *** {% embed url="" %} ## 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**

Cutting MAXComposite on CO₂ Laser (2X speed)

### **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) {% hint style="danger" %} **Diode lasers are generally not recommended** for cutting MAXComposite. {% endhint %} {% hint style="danger" %} If you notice plastic spraying up onto the surface or excessive smoke coming up from the cut line, it is likely that it is not fully cut through. {% endhint %} ### **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.

Using a table saw to process MAXComposite

**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.

CNC Routing 0.2in MAXComposite (2X speed)

**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)** {% hint style="danger" %} **Avoid excessive heat buildup**, as this can cause melting and material deposits on the bit. {% endhint %} *** ## **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**

The effects of Loctite, polycarbonate (left) and MAXComposite (right)

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.