The plastics have became
inseparable part human life, the use of plastic and products made by plastics
are all around us, plastic has been chosen as alternative to metal post second
world war, the popularity of plastic is due to its versatile nature of taking
any shape and can be made hard enough for by selective chemical and heating
process. Plastics are divided in to two categorizes 1) Thermoplastic 2)
Thermosetting Plastic.
Thermoplastics are relatively
soft in nature and can be heated, moulded in shapes various times. Mostly find
application in household such as mug, toys etc. where strength and toughness of
plastic product is not desired. On other hand Thermosetting plastics are
generally strong and resistant to heat, but they melt the first time they are
heated to a high enough temperature and harden (set) permanently when cooled.
They can never be melted or reshaped again. Hence rapid heating is desired for
melding the thermosetting plastics, which is difficult to achieve from the
conventional heating system, it becomes an ideal application for RF heatingsystems because RF heaters quickly and uniformly heats the thermoset plastic
resin to softening point for the for molding.
Issues with Conventional process of molding:
Heating
certain plastic material in a press, even in powder structure, causes the
grains by the hot die to "set" before alternate grains in the volume
of the mold get to be delicate. That brings about poor filling of the mold
which causes faulty completed parts. Preheating the powder in a stove or on a
hot plate alleviates this issue sort of, yet, best case scenario the grains get
to be sticky and are hard to handle rapidly without automation. In the event
that they are heaped up the heating is not uniform.
To help
the taking care of issue, plastic powder is regularly compacted under high
weight to make performs. They have consistent shapes, frequently round barrels,
and might be effectively moved about by hand. Beforehand the thickness of
performs was constrained by worries about curing or setting the compound on the
outside without heating the inside. This likewise causes poor filling of the
mold holes and harms the presence of the last casting by creating uneven shine
and voids.
Radio Frequency
preheating for the molding
Radio Frequency heating provided
an excellent solution to the problem of rapid uniform heating of performs
because it heats the entire performs up to the molding temperature quite
uniformly in 2 to 60 seconds. Time is subsequently available for manually or
automatically transferring performs to the mold cavity and closing the press
before the full curing takes place. The results are good fill and excellently
finished parts. KERONE manufactures the customized RF heaters that will be best
suited for the process need to preheating plastic for the molding purpose.
List of Plastic products that need RF heating
Plastics products manufacturing
that typically uses Radio Frequency heating are for pot handles, circuit
breaker cases, instrument cases, automotive distributor and other electrical
parts, telephones, radio/TV cabinets, washing machine agitators, dinner ware,
knobs, telephone parts, telephone central office equipment, blower impellers,
lens mounts, encapsulations for microelectronic components, fabricated from
polyester resins reinforced with fiberglass (FRP), molded disc brake cylinders,
heat resistant handles, electrical plugs, switches, circuit boards and
semiconductor encapsulation and a myriad of others.
Advantages of RadioFrequency Heating system
1) Speeding
the process: The shorter preheating time and uniform temperature results in free flow of
soften resin to mold.
2) Increased
part lifespan: Differential curing allows for lower
internal stresses while providing an even cure with no overheated or uncured
areas.
3) Less
mold wear: Softened resin flows easily into mold
and set down after compression only hence it increases the life of Mold.
4) Increase in Final Output: RF preheating permits bigger product(s)
to be created than might be delivered by different means.
5) Improved Output quality: Rapid speed of softening result in the
molding of plastics before they start setting.
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