THIẾT TRÌNH THIẾT KẾ CHẾ TẠO KHUÔN MẪU ĐỦ 25 BÀI_13_EN

(Hot runner)
Presentation: How to calculate, design hot channel system for computer mouse shell


Mission

Putting hot plastic into the cavity when hot plastic line comes out from presses and keeps the molten plastic in the
channel system.


Hot asphalt supply system


Technical requirement

• Temperature distribution uniformity
• Must minimize the potential loss of pressure
• - Ability to control the status as a valve vents the heat (thermal):


Structure

• - Silver spray stem (sprue bushing).
• - Funnel plastic distribution to the nozzle (Manifold).
• - Nozzle (Nozzle).
• - Oral Spray (Gate



Bạc cuống phun (Sprue bushing)

• If the temperature of this area is too low for sensitive materials at high temperature, the surface of the product is not quality. So to
heat the stem silver spray. Here is a more detailed standards and large firms produce very good quality.



The silver-stemmed type spray in hot channel
1-


Kênh dẫn Manifold

• Manifold is used when spraying indirectly through multiple vents, manifold acts as a distributor of
plastic sheet from the hot arm of the machine to the cavity.


Composition and characteristics

(1) Body manifold: made from alloy or stainless steel.
(2) Plastic Free: for liquid plastic can flow in it, requires increasingly smooth as possible.


The channel type Manifold


Design Manifold good, not good


Mold structure for Manifold

4 - Firmly grip

Plates containing nozzles (Nozzle cavity plate) must be
made with niches containing Manifold and must have
clearances of at least 10mm shell clamping bolts
quanh.Cac Manifold must close as possible to ensure the
grip.


The size of a Manifold important

Size M: thickness of the manifold
M1 Dimensions: width of manifold
Size J2: the canal diameter plastic in the manifold


Calculation of thermal expansion

LR = LF (1 - α (TR - TF)) (mm)
Inside:
LR is the size of the manifold (mm).
LF is the size of the manifold in the mold (size when expanded) (mm).
TR is the manifold temperature (° C).
TF is the temperature of the mold (° C).
α is the coefficient of thermal expansion (1 / ° C).


Nozzle)

(1) Nozzle tip

(2) Gaskets
(3) Closing the valve
(4) Heating equipment
(5) Thermocouples
(6) Body Nozzle


• - Sprinklers are the most important details, difficult choices and fabrication of an HR
system, it must meet several demanding.

• Nozzle is heated from inside or outside


Heated nozzle in


Heated nozzle OUT


Nozzle type isolation


Calculation of Nozzle length expansion

• Actual length = L +? L of Nozzle + q
• L: the length of the selected type Nozzle (mm).
• ? L: is the thermal expansion value of Nozzle (mm).
• q: the vent openings (mm).

Giá trị ΔL được xác định như sau:
ΔL= LF – LD = LD x α x (TR – TF) (mm)


Gate