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Hot Runners 16 MoldMaking Technology —— APRIL 2017 These high-resolution images of the mobile device housing project demonstrate achievable gate quality when the right equipment and processing conditions are used. The high-resolution image on the left shows the gate, and the image on the right shows the molded plaque with good gate quality. FIGURE 5 Before processing, the resin has to be properly dried at 120-150ºC for three to five hours. If the resin is not properly dried, then splay or bubbles could form in the part, which can affect part qual- ity. Keep in mind that injection speed, hold time, hold pressure, shot size and processing temperatures (melt and mold) influence part and gate quality, so each of these parameters must be fully optimized to establish a wider process- ing window, increasing part quality and improving repeatability. To optimize part fill time, several runs at different injection speeds at a set melt temperature of 385ºC and mold temperature of 170ºC were conducted. These runs started with a high injec- tion speed of 300 mm per second and then slowed down to 25 mm per second. The results demonstrated that the part needed to be filled faster. The optimum fill time was determined to be 0.32 sec- onds, and peak pressure was 10,954 psi (see Figure 4, page 15). High-resolution imaging of the gate demonstrated the gate quality that can be achieved with the right equipment and processing conditions (see Figure 5). Gate posting (vestige) was also observed during processing with melt temperatures at 390-395ºC. Lowering the melt temperature resolved the issue. Also, ripples and grooves on the part surface were observed at low injec- tion speeds. This was due to solidifica- tion occurring too quickly. The high walter-tools.com/us The Ikon of a new performance class The Supreme DC170's unique and innovative margin design ensures that the carbide's strength is exactly where you need it; right behind the cutting edge, facing the cutting forces - precisely where greater stability significantly increases productivity. This increases the process reliability, tool life and quality – while simultaneously reducing your manufacturing costs. The Supreme DC170 – The Ikon that gives drilling a new look. Supreme DC170 Visibly different, clearly leading the way.