1. About Rotational Moulding: Rotational moulding, known also as rotomolding or rotocasting, is
a process for manufacturing hollow plastic products. For certain
types of liquid vinyls, the term slush molding is also used.
Rotational molding has particular advantages in terms of relatively
low levels of residual stresses and inexpensive molds. Rotational
molding also has few competitors for the production of large (>
2 m3) hollow objects in one piece. Rotational molding is best known
for the manufacture of tanks but it can also be used to make
complex medical products, toys, leisure craft, and highly aesthetic
point-of-sale products.
The process begins with specially developed and uniquely applied
resins. They can include plastisols, polyethylene, polycarbonate,
acetate butyrate, polyamide, elastomers, polyurethane,
polypropylene, ethylene vinyl acetate and fluorocarbons. Some of
the most advanced work is being done with cross-linked polyethylene
and even nylon.
The principle of rotational molding of plastics is simple.
Basically the process consists of introducing a known amount of
plastic in powder, granular, or viscous liquid form into a hollow,
shell-like mold.The mold is rotated and/ or rocked about two
principal axes at relatively low speeds as it is heated so that the
plastic enclosed in the mold adheres to, and forms a monolithic
layer against, the mold surface. The mold rotation continues during
the cooling phase so that the plastic retains its desired shape as
it solidifies. When the plastic is sufficiently rigid, the cooling
and mold rotation is stopped to allow the removal of the plastic
product from the mold. At this stage, the cyclic process may be
repeated. The basic steps of (a) mold charging, (b) mold heating,
(c) mold cooling, and (d) part ejection are shown in Figure below.
Advantage
Design flexibility allowing complex geometry
· Cost saving - Projects of 50 to 30,000 are ideal
· Molds cost less then other molding methods
· Parts offer strength and durability
· Stress free parts
· Short lead times on production
· Consistent wall thickness
· Limited materials waste
· Small to very large hollow parts can be produced
· Part surfaces can have various textures
Our Company
professional designer for rotational mold in China
MOULD PROCESS:
1.FOAM PROTOTYPE
3.Polish
4.Mold framing
5. Testing & Package
1. Design & Engineering Services
Beginning a new project starts with a solid design concept. Our
in-house Design & Engineering Department will help advise and
manage your project all the way to a produced rototmolded part.
Whether your project is a rough idea or a 3D model, we believe in
developing a partnership early on with the customer and strive to
reduce lead times and so both parties benefit from rotational
molding.
2. Rotational Molding Design Guides
· Minimum wall separation 5x wall thickness (a)
· Minimum wall separation 3x wall thickness (b)
· Uniform wall thickness ± 20% (c)
· ±10% is considered precise tolerance (c)
· Wall thickness .090" to 1.00" (c)
· Different wall thickness can be produced based on functional
requirements
· Large flat areas need a crown or ribs (d)
· Corners need minimum radius of 3/16"(e)
· Structural strength
· Reinforcing ribs - average proportions
· Height 4x wall thickness (f)
· Width 5x wall thickness (g)
·Kiss-off ribbing (h)
· Part Finishing and Secondary Operations
Note: Design Guide information is based on Linear Low Density
Polyethylene (LLDPE) other materials tolerance can vary.
3. Cast Tooling Pattern
When your design is finalized the pattern production begins. Most
commonly patterns are CNC machined from the 3D model, but other
options are available.
After the pattern is reviewed and signed-off on, the followers for
determining the parting lines are constructed. Next, the pattern
goes through the sand ramming process creating the cope and drag.
Then our Tooling Department is ready to pour the tool.
4.Rotational Molding Plastic Parts
Rotational Molding, also called rotomolding or rotocast, is a
thermoplastic process for producing hollow parts by placing powder
or liquid resin into a hollow mold and then rotating that tool
bi-axially in an oven until the resin melts and coats the inside of
the mold cavity. Next the tool is cooled and the part is removed
from the mold.
Four steps in manufacturing a rotational molded part
1. Fill the mold with a polymer material
2. Heat tool in oven to melt material
3. Cool tool to solidifies the part
4. Remove part from the tools
Company Infomation:
SHANGHAI FRANCOM ROTOMOLDING Combined professional experience in
varied and demanding rotational molding applications, exceeding
customer's expectations both nationally and internationally for
over 10+ years.
We will provide you with a true one-stop shop for all of your
product design, prototyping, tooling and full-scale manufacturing
needs.
We offer significant differences compared to other molders
including:
· Project Management
· Design and Engineering
· Research and Development
· Rapid Prototyping
· In-house Cast Aluminum Tooling
· Rotational Molding (Rotocasting)
· Multi layer Part
· Molded-in Inserts
· Mold In Graphics
· In Mold Painting
· Secondary Operations
· Post Mold Finishing
· Light Assembly
· Mold On Graphics
· Post Mold Painting
· Product Testing
· Graphic Design and Layout
· Packaging and Shipping
FAQ:
Q: Are you trading company or manufacturer ?
Q: How long is your delivery time?
A: Generally it is 35 days after confirming drawing and receive
advanced payment.
Q: Do you provide samples once open mould?
A: Yes, we could offer the sample for free charge but do not pay
the cost of freight.
Q: What is your terms of payment ?
A: 30% advanced payment, the balance before shippment.
Contact Information:
Contact person: Chris Zhu
Mob/ wechat/whatsapp:+86 15021263620
Email: chris_shjc@126.com
Skype: christy_faxi