CNC prototype processing is a highly precise manufacturing method that requires careful attention to every detail to achieve the desired results. Whether you’re working with plastics, metals, or other materials, following the right precautions can make all the difference in the quality, functionality, and cost – effectiveness of your prototype. Let’s explore the essential steps and considerations you need to keep in mind.
Material Preparation: Laying the Groundwork
Before the machining process even begins, proper material preparation is crucial to avoid common issues down the line.
- Bubble treatment is a top priority, especially when working with plastics that require mixing with a hardener. Bubbles can form during this mixing process, which can weaken the prototype’s structure. If you have access to a vacuum machine, use it to remove air bubbles effectively – studies show that vacuum treatment can reduce bubble formation by up to 90%. If a vacuum machine isn’t available, you can reduce the amount of curing agent added by 10 – 15% to minimize bubble formation, though this method is less effective than vacuuming.
- Material selection is another vital step. CNC prototype machining works with a wide range of materials, including various plastics and metals. When choosing a material, always consider the prototype’s purpose and functional requirements. For example, if the prototype needs to withstand high stress, a durable plastic like POM or a metal like aluminum might be better choices. If it’s a decorative prototype, a plastic with a smooth surface finish could be ideal.
Mold and Design Considerations: Preventing Sticking and Deformation
Proper mold preparation and design adjustments can help avoid two major issues: mold sticking and product deformation.
- Mold sticking prevention starts with preparing the model before mold opening. If the model has a rough surface or a complex design, sand it smooth using sandpaper with a grit size between 400 – 800. After sanding, clean the model thoroughly to remove any dust or debris. Then, apply a release agent evenly across the mold surface. This simple step can reduce the risk of sticking by up to 80%, saving you time and effort in removing the prototype from the mold.
- Avoiding product deformation requires choosing the right plastic hardness based on the product’s size and complexity. For small or delicate products with intricate details, use softer plastics with a hardness between 10 – 20 Shore A. This makes demolding easier and reduces the chance of damaging the details. For larger, more robust prototypes, you can opt for harder plastics with a hardness of 30 – 50 Shore A to ensure structural stability.
Curing Agent and Process Control: Getting the Mix Right
The dosage of the curing agent and the choice of machining processes play a significant role in the prototype’s quality.
- Curing agent dosage adjustment is essential, as it’s highly dependent on temperature. In high – temperature environments (above 25°C), reduce the curing agent amount by 10 – 15% compared to the standard dosage. Using too much curing agent can make the mold hard and brittle, increasing the risk of cracks. On the other hand, using too little can prolong the curing time significantly – sometimes by 50% or more – delaying the machining process.
- Selecting the right machining processes is key. CNC prototype machining involves various processes such as milling, turning, and drilling. Each process has its specific applications. Milling is great for creating flat surfaces and complex shapes, while turning is ideal for cylindrical parts. For example, if your prototype has a cylindrical handle, turning would be the best process to achieve a smooth, even surface. Always match the process to the prototype’s specific needs to ensure precision.
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