CN101549546A

CN101549546A - Temperature changing unit of micro injection molding die

Info

Publication number: CN101549546A
Application number: CNA2009103010682A
Authority: CN
Inventors: 刘莹; 宋满仓; 王敏杰; 祝铁丽; 赵丹阳
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2009-03-24
Filing date: 2009-03-24
Publication date: 2009-10-07
Anticipated expiration: 2029-03-24
Also published as: CN101549546B

Abstract

A temperature changing unit of micro injection molding die belongs to the micro injection molding die technology field. The die changing unit includes imbibing core hot pipe, semi-conductor refrigeration tablet, copper plate, water tanks, electric thermo-couple and temperature-controlled instrument. One side of the imbibing core hot pipe is interposed into die mould cavity plate while the other one into the copper plate, both sides of the touch with the semi-conductor refrigeration tablet with the other side touches with water tanks. The upper and down surface of semi-conductor refrigeration tablet are coated heat diffusion layer, electric thermo-couple touches with the surface of die mould cavity and feeds back its temperature to temperature-controlled instrument, and decides to heat or cool down by the computer controlling the current direction of semi-conductor refrigeration tablet. The changing unit can implement the changing control to the micro injection molding die and the accurate uniform temperature-controlled to the formwork. The set has compact conformation, can flexibly adapt the finite space between the injection moulding machine and die, which diminished the heat distortion of formwork. This changing unit can be applied to the injection molding procedure of tiny mould pieces, which accounts for the difficulty of controlling temperature during the micro injection molding procedure.

Description

A kind of temperature changing unit of micro injection molding die

Technical field

The invention belongs to the micro injection molding die technical field, relate to a kind of temperature changing unit of micro injection molding die.

Background technology

Micro injection molding is a kind of faster emerging technology of development in recent years, is that a kind of batch process that can carry out repetition is complicated and the manufacturing technology of precise fine structure plastic is arranged, and is with a wide range of applications in MEMS (MEMS) field.Utilize the member in the micro-injection moulding mould molding MEMS, compare, have low cost of manufacture, with short production cycle, moulding process is simple and the member quality is easier to advantages such as assurance with the silica-base material member that is applied in the MEMS field at present.

In the injection mo(u)lding mold filling process, when polymer melt contacts with the low temperature mold cavity wall, heat transmission between melt and die cavity wall can make the melt heat lose rapidly, melt forms condensate layer at die cavity wall place, condensate layer is constantly to internal extended, make the melt flow passage cross section constantly reduce, the melt flows resistance increases, the filling difficulty.Micro injection molding plastic size is little, precision is high, and quality is following or have micron-sized micro-structural on it at 1 gram usually, and the condensate layer influence is understood more remarkable, so adopt Gao Mowen usually.In addition, Gao Mowen can also eliminate other forming defects such as weld mark, molecular orientation, improves the uniformity of goods.But the raising of mold temperature certainly will increase the cool time of plastic in mould, and the production cycle is prolonged.Therefore, mould can very fast intensification when desirable humidity control system was mold filling, and mold temperature is reduced to calcining temperature fast during cooling, and promptly mould can be realized alternating temperature control.

At present, mould alternating temperature mode mainly contains following several: electrical heating water-cooled, infrared ray heating water-cooled, eddy-current heating water-cooled, film resistor heating water-cooled, compound die wall thermal insulation-heating etc.Wherein the electrical heating water-cooling pattern is used more extensive, simple in structure, cost is lower, its shortcoming is that the Electrothermal ring thermal resistance is bigger, and easily forms the too high phenomenon of local temperature, and certain thermograde is arranged, heat inhomogeneous, cause the template thermal stress deformation easily, and cooling the time need cool off heater coil simultaneously, thermal loss is big.And infrared ray heating water-cooled and eddy-current heating water-cooled need be opened mould earlier before the mould mold filling, by manual or manipulator mold cavity is heated, matched moulds filling fast then increases operating procedure, and after the beginning mold-closing injection, with regard to uncontrollable die plate temperature.Film resistor heating water-cooled and compound die wall thermal insulation-heating etc. are except that the shortcoming with electrical heating water-cooled, and structure is complicated, need have the new material that heat conduction is good and insulation is good concurrently, and makes difficulty.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of temperature changing unit of micro injection molding die, overcomes the shortcoming or the deficiency of above-mentioned mould changing device, promotes the development of micro injection molding die technology.

Technical scheme of the present invention is as follows:

A kind of temperature changing unit of micro injection molding die comprises imbibition core heat pipe, conductor refrigeration sheet, copper coin, water tank, thermocouple and temperature controller.

A side of imbibition core heat pipe is inserted in the mold cavity plate in this changing device, and opposite side inserts in the copper coin; The copper coin both sides all contact with the conductor refrigeration sheet, and the opposite side of conductor refrigeration sheet contacts with water tank; The upper and lower surface applied heat-conducting layer of conductor refrigeration sheet.

Thermocouple contacts its temperature of feedback to temperature controller with the mold cavity surface, by control semiconductor chilling plate sense of current, realizes mold heated cooling and accurate temperature controlling.In the mold cavity plate, add heat insulation layer around the die cavity piece to reduce thermal loss, improve heat transfer efficiency.

During actual the use, can adopt the coupling of multi-disc semiconductor chilling plate, place it in the copper coin both sides.

Effect of the present invention and benefit are: adopt this device to realize alternating temperature control and to the accurate even temperature control of template to micro injection molding die.This apparatus structure compactness, can the flexible adaptation injection machine and mould in the confined space, reduce the thermal deformation of template, avoid the influence of temperature-controlling system to injection machine system.This mould changing device can be applied to the injection molding process of small plastic, solves the mould temperature control difficult problem in the micro injection molding process.In sum, the present invention will further improve little injection mold technical merit, promote the application of little injection-molded item in the micro mechanical system field.

Description of drawings

Fig. 1 is the changing device schematic diagram.

Fig. 2 (A) is the microfluidic chip structure schematic diagram.

Fig. 2 (B) is the A-A cross section enlarged drawing of Fig. 2 (A).

Fig. 3 is micro-fluidic chip mold integral assembling schematic diagram.

Among the figure: 1 imbibition core heat pipe; 2 conductor refrigeration sheets; 3 water tanks; 4 mold cavity plates; 5 temperature controllers; 6 computers; 7 copper coins.

The specific embodiment

Be described in detail specific embodiments of the invention below in conjunction with technical scheme and accompanying drawing.

Present embodiment is used for the typical product microfluidic control chip injection molding die of micro injection molding, chip structure as shown in Figure 2, profile is a slab construction, and two diesis shape microchannels are arranged on it, cross sectional shape is dark, the wide rectangles of 80 Xie of about 50 Xie of size.

The embodiment step is as follows:

Step 1: select different size imbibition core heat pipe 1 and conductor refrigeration sheet 2 according to the mold cavity block size, corresponding size copper coin 7 and water tank 3 assemble as shown in Figure 3, and a side of imbibition core heat pipe 1 is inserted in the mold cavity plate 4, and opposite side inserts in the copper coin 7; Copper coin 7 both sides all contact with conductor refrigeration sheet 2; Semiconductor chilling plate 2 upper and lower surfaces coating heat-conducting layer, opposite side contacts with water tank 3, and logical cooling water is used for 2 heat radiations of conductor refrigeration sheet in the water tank 3.

Step 2: thermocouple contacts with the mold cavity surface, feed back its temperature to temperature controller 5, when the die cavity temperature is lower than the heating-up temperature of computer 6 settings, the one side heat radiation that conductor refrigeration sheet 2 contacts with copper coin 7, heat reaches mold cavity plate 4 to its heating by imbibition core heat pipe 1, when reaching design temperature, carry out operations such as chip injection, pressurize;

Step 3

Computer 6 is set chilling temperature, and by temperature controller 5 control semiconductor chilling plates 2 senses of current, the one side that contacts with copper coin 7 heat absorption is cooled off by 1 pair of mold cavity plate 4 of imbibition core heat pipe, when reaching chilling temperature, carries out operations such as chip ejects.

Step 4

As shown in Figure 1, by computer 6 program setting temperature control curves, repeating step 2 steps 3 realize the control of mould alternating temperature.

Claims

1. temperature changing unit of micro injection molding die, comprise imbibition core heat pipe (1), conductor refrigeration sheet (2), water tank (3), thermocouple and temperature controller (5), copper coin (7), it is characterized in that: a side of imbibition core heat pipe (1) is inserted in the mold cavity plate (4) in this changing device, and opposite side inserts in the copper coin (7); Copper coin (7) both sides all contact with conductor refrigeration sheet (2), and the opposite side of conductor refrigeration sheet (2) contacts with water tank (3); The upper and lower surface applied heat-conducting layer of conductor refrigeration sheet (2); Thermocouple contacts with the mold cavity surface and feeds back its temperature to temperature controller (5), mold cavity plate (4) is heated or cooling with definite by computer (6) control semiconductor chilling plate (2) sense of current.

2. a kind of temperature changing unit of micro injection molding die as claimed in claim 1, its feature also is: multi-disc semiconductor chilling plate (2) coupling places it in copper coin (7) both sides.

3. a kind of temperature changing unit of micro injection molding die as claimed in claim 1, its feature also is: add heat insulation layer in mold cavity plate (4) around the die cavity piece.