QUESTIONS 1. What constraints are necessary for biaxial rotation to evenly coat

Question

QUESTIONS 1. What constraints are necessary for biaxial rotation to evenly coat the mold in a rotational molding process? 2. Discuss three ways to alleviate the sticking of a part to the molá. 3. £xplain how polyethylene is crosslinked in a rotomolding operation. 4. Describe a technique for forming a part with an outer coating and a different inner material using rotomolding. 5. Why is there a limit on the thickness of parts that can be reasonably made by 6. 7. What is the major limitation on the distance between walls in a doubie-walled ca 8. Give five part characteristics that indicate a poorly fused part. rotomolding? Describe why fillers and other additives may increase or, in some cases, decrease rotomolded part mechanical properties. rrying case made by rotational moiding?

Explanation / Answer

1. Biaxial rotation must have both axes rotating simultaneously. The frequency of rotation should be different for each axis, and the rotational frequencies should not be even multiples of each other.

2.

3. In roto molding, polyethylene is filled inside mold and then mold is rotated bi-axially. So that inside the mold polyethylene will also move in mold and will take shape of the mold. Now due to rotation in two directions polyethylene molecules will get cross linked. From oven outside high temperarure is provided which will in turn increase air pressure inside. This increased air pressure will also help in cross linking of polyethylene molecules.

4. This is two stage process, First using outer coting material, a part is made from rotomolding operation. After completing process, part is not removed from the mold and new inner material is filled inside the roto mold. So again mold is bi-axially rotated and finally part with two different material at inner and outer is generated in roto mold.

5. Since we know that this process largly depends upon bi-axial rotation of mould and due to that rotation, material powder inside get centrifugal force away from center and it tries to stick to the mold wall due to high temperature and pressure. So that there is limitation is wall thickness because if high thickness is required then part strength can get reduced.

8.

9. In part performance weight of resin charge is important beacause when mold is rotating in bi-axial dircetion, due to weight of resin, some force will apply on mold wall and this force will make the resin is sticking to the mold wall.

10. Due to high melt index resin will have high flow. Since this part is compicated, we required high flow characteristic so that resin can reach to the all the portion of the mold. We will use high melting index 30.

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.