ANTEC 2008射出成形發展趨勢 · acquisition of the molding process was conducted using a CCD (Charged-Coupled Device) camera. It was found that the flow hesitation is dependent

1財團法人塑膠工業技術發展中心

ANTEC 2008射出成形發展趨勢

財團法人塑膠工業技術發展中心

林忠志Tel:04-23595900分機:703

E-mail:[email protected]


何謂 ANTEC ?

1. ANTEC由 SPE)主辦，是全球塑膠業最重要的新知與技術發表的研討會。

2. SPE學會每年都會在美國舉辦最負盛名、規模最大的塑膠專業科技會議ANTEC (Annual Technical Conference)，，討論塑膠產業最新的研究方向和新技術，在全球重要性不出其右。

3. 每會期ANTEC接獲全球各地專家學者投稿約1,500篇，遴選約500-600篇發表，其專業及重要性可謂一時之選

4. 來自全球塑膠業項尖的公司、學術與研究單位，都會一同參與其中，分享與交流彼此的知識、經驗與技術。


1. 射出加工成型領域

2. 模具技術領域。

3. emboss technology

4. 其他

內容綱要


射出加工成型領域

Effect of Cavity Pressure Profile on the Cellular Morphology of Injection-Molded HDPE Structural Foams3Effect of Cavity Pressure Profile on the Cellular Morphology of Injection-Molded HDPE Structural Foams4

EFFECT OF PROCESSING PARAMETERS ON FLOW HESITATION WITHGLASS-FILLED REINFORCED THERMOPLASTICS: EXPERIMENTAL INVESTIGATION WITH DIRECT VISUALIZATION

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A COMPARISON OF SEVEN TRANSFER METHODS FOR VELOCITY TO PRESSURE SWITCHOVER1

RAPID MOLD HEATING BY INDUCTION HEATING AND ITS APPLICATION TO THIN-WALL INJECTION MOLDING3Development of Gas-Assisted Dynamic Mold Temperature Control System and Its Application for Micro Molding4

COUPLED FEA SIMULATION OF THE DEMOULDING PROCEDURE OF INJECTION MOULDED PARTS2

SIMULATION AND VERIFICATION MOLD TEMPERATURE VARIATION OF PULSED-COOLING1

模具技術領域


emboss technology領域

HOT EMBOSSING OF HIGH ASPECT RATIO SUB-m STRUCTURED SURFACES FOR MICRO FLUIDIC APPLICATIONS3

HOT EMBOSSING WITH AN ENLARGED PROCESS WINDOW2

HOT EMBOSSING OF DISCRETE MICROPARTS1

NEW TECHNOLOGY TO VARY THE RADIAL THICKNESSDISTRIBUTION OF THE PARISON IN EXTRUSION BLOW MOULDING3

EVALUATION OF PATTERNED JOINT DESIGNS FOR ULTRASONIC WELDING OF HDPE NANOCOMPOSITES2

THROUGH TRANSMISSION INFRARED WELDING OF POLYPROPYLENE NANOCLAY COMPOSITES1

其他領域


A COMPARISON OF SEVEN TRANSFER METHODSFOR VELOCITY TO PRESSURE SWITCHOVER

AbstractMolding processes typically utilize a velocity controlled filling stage followed by a pressure controlled packing stage. The short term and long term effectiveness of seven different switchover methods are considered, including: 1) ram position, 2) injection time, 3) machine pressure, 4)nozzle pressure, 5) runner pressure near the sprue, 6)cavity pressure near the gate, and 7) cavity temperature at the end of flow. The results indicated that the machine controlled switchover methods (ram position, injection time, and machine pressure) had a lower short term variation in the quality of the molded parts, but the other switchover methods were more robust with respect to rejecting long term process variation.

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討論保壓切換點的選擇方式與效果

(ram position, injection time, and machine pressure) 比較佳


TRANSFER FOR VELOCITY TO PRESSURE SWITCHOVER

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This study investigates the effect of processing parameters on flow hesitation with glass-filled reinforced (GFR) polymers. An inherently difficult to fill fishbone cavity geometry was utilized throughout the study where the side appendages along the main direction of flow are of varying cross-section. An L9 Taguchi method design of experiments (DOE) was performed for each material –PP, PBT and LCP. Parameters varied include mold temperature, melt temperature, injection rate, and packing pressure. To further investigate the flow hesitation dependency of the materials processed, direct visualization of the flow in real time was performed byincorporating a transparent window in the mold tool. Design limitations and constraints were thoroughly reviewed and are presented. Video imaging andacquisition of the molding process was conducted using a CCD (Charged-Coupled Device) camera. It was found that the flow hesitation is dependent of the material being processed, but is also heavily dependent on the melt temperature and packing pressure. Of the three materials processed, LCP exhibited superior flow properties, i.e. minimal flow hesitation, whereas PP and PBT were significantly affected by the processing conditions employed. LCP was the only polymer which yielded a completely filled part. In general, PP exhibited better flow properties than PBT.

EFFECT OF PROCESSING PARAMETERS ON FLOW HESITATION



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結論The goal of this study was to investigate the effects of processing parameters on flow hesitation within an injection-mold cavity. Flow hesitation stems from processing related issues with parts that have features which are relatively harder to fill than the main part itself. This retarded filling process may also have negative ramifications on part quality especially with shear sensitive polymers since premature freezing off may occur due to hesitation effects and unbalanced internal flow. A thorough investigation of the effects of processing parameters on the part quality was carried out experimentally for three different glass-filled reinforced polymers – PP, PBT, and LCP. The final part mass was used as the performance metric. It was found that the flow hesitation is dependent of the material being processed, but is also heavily dependent on the melt temperature and packing pressure. Failure to pack the part sufficiently when the V/P switch is engaged results in short shots of the smaller, more flow resistant, appendages. Of the three materials, LCP exhibited superior flow properties and produced a completely filled part. In general, PP exhibited better flow properties than PBT. Fine tuning of the processing parameters of the other materials may produce a completely filled part, but will most likely result in poor production rates.



COUPLED FEA SIMULATION OF THE DEMOULDING PROCEDURE OF INJECTION MOULDED PARTS

0722

A reasonable design of the injection mould has to guarantee that the mouldedpart can be demoulded without damaging either the ejection system in the mould or the part. In the conventional mould design this damaging occurs at the very end of the development process of the injection mould when it is already assembled. A simulation procedure is presented which enables the mould maker to mechanically layout the demoulding system. It combines a process simulation with a structural analysis and hence maximises the advantage of using CAE.


COUPLED FEA SIMULATION OF THE DEMOULDING PROCEDURE OF INJECTION MOULDED PARTS

0722


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Nowadays most products need high quality of surface appearance which can be achieved usually at high mold temperature. Pulsed cooling is one of the variable mold temperature controls without significant increase in cycle time. In this study, pulsed cooling was applied in the injection and packing process for about 0.3 seconds, and mold temperature can be higher than that in conventional injection molding by about 5℃. The mold temperature can also be lowered down efficiently in the cooling process. Simulation based on Moldex3D® was carried out, and simulated predictions show similar trend in mold temperature rise and in fair coincidence with the experimental results.

MOLD TEMPERATURE VARIATION OF PULSED-COOLING

利用PULSED-COOLING的冷卻技術來達到射岀件的表面品質


SIMULATION AND VERIFICATION MOLD TEMPERATURE VARIATION OF PULSED-COOLING

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SIMULATION AND VERIFICATION MOLD TEMPERATURE VARIATION OF PULSED-COOLING

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MOLD TEMPERATURE VARIATION OF PULSED-COOLING

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Because coolant doesn’t take much heat out by the pulse cooling in the filling stage, the plastic’s heat can be transferred to the surface of the mold. This ensures higher temperature in the filling of the plastic, improves replication accuracy, structural strength, surface quality, and etc. Therefore, the purpose of this study is accomplished. From the raising temperature in one cycle, the results show that if the coolant temperature are kept the same and flow crossing sections and distance are keptconstant, according to the heat transfer formula, the mold with higher temperature will take away more heat:

結論


THROUGH TRANSMISSION INFRARED WELDING OF POLYPROPYLENE NANOCLAY COMPOSITES

0379

Through transmission infrared welding of polypropylene nanocompositeswith 0, 3, and 6 wt% nanoclay was evaluated. Because polypropylene samples with nanoclay additive were found to have low transmissionrates, it was challenging to obtain acceptable welds. The shear force required to fail welded samples decreased significantly with increasing nanoclay percentage.


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ConclusionsWelding of polypropylene nanocomposites was investigated using through transmission infrared techniques. Lap joint amples were welded using polypropylene nanocomposite with 0, 3, and 6 wt% nanoclay using a quasi-simultaneous approach. Weld samples were evaluated using optical microscopy and weld shear strengths were determined. The effects of varying nanoclay concentration and weld parameters were explored. Transmission experiments allowed for a prediction of the laser energy at the weld interface for each combination of nanoclayconcentration and laser power. Exponential trend lines allowed for an approximation of the amount of laser energy reflected. Transmission rates were found to




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decrease with increasing nanoclay content. For each 3 wt% addition in nanoclay, there was a reduction in transmission of near 10% for full-thickness (4.5 mm) samples.The weld failure forces decreased with increasing nanoclayconcentration. However, the laser power was not adjusted to maintain identical laser energy at the weld interface for each nanoclay concentration. More aggressive welding conditions were required to weld nanoclaycontaining polypropylene samples, and the probability of polymer degradation increased. Because polypropylene samples with nanoclay additive were found to have high absorption and low transmission rates, it was challenging to obtain acceptable welds. Increasing the infrared exposure time and laser power resulted in overheating and pitting at the weld interface. The maximum failure strengths achieved were 29.145 MPa, 19.8 MPa, and 17.46 MPa for 0, 3, and 6 wt% nanoclay, respectively. Although there was a significant decrease in weld failure force with nanoclay addition, the weld failure forces achieved for nanocomposite samples using TTIR were in-line with those from previously explored welding processes. Nanoclay composites offer challenges for the TTIR process, such as the reduction of infrared transmission, but the process proved to be feasible for polymeric nanocomposites.



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EVALUATION OF PATTERNED JOINT DESIGNS FOR ULTRASONIC WELDING OF HDPE NANOCOMPOSITES

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The ultrasonic weldability of high-density polyethylene (HDPE) nanocomposites was investigated using four different energy director butt joint designs with loadings of 0, 3, and 6 wt% nanoclay. Patterned surfaces were incorporated in an attempt to allow nanoclay platelet alignment on multiple planes inside the weld region. Samples were welded using a one-factor-at-a-time approach varying weld time, weld amplitude, and weld force. Weld tensile strengths were compared for the different clay contents and joint patterns.



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ConclusionsUltrasonic welding was studied using joint designs with patterned surfaces in an attempt to increase the weldability of thermoplastic nanocomposites. As would be expected, the patterned surfaces had no effect on the strength of the unfilled HDPE samples. For the 3 wt% nanoclay the patterned surfaces had a small if any effect on weld strength. However, for the 6 wt% nanoclay, thelarger patterns (large knurl and saw-tooth) had a significant improvement in weld strength compared to the flat tee, but the welds were still very weak compared to the bulk.Overall, the incorporation of patterned joint designs did not significantly improve the weld strengths of HDPEbased nanocomposites. However, the concept of introducing patterned surfaces at the weld interface does hold promise showing that it is possible to encourage nanoclayorientation on multiple planes and not just one. Although the weld strengths achieved showed little benefit for the patterns used, this work can serve as the basis for designing new joints and patterns that retain more of their height and thereby bring about a greater improvement in strength.


RAPID MOLD HEATING BY INDUCTION HEATING ANDITS APPLICATION TO THIN-WALL INJECTION MOLDING

0811

AbstractThe present study covers a theoretical and experimental investigation of induction heating in order to rapidly raise the mold temperature. Through the coupled Finite Element (FE) simulation,it is observed that the mold surface temperature is raised up to200°C in 3 seconds. This induction heating is applied to injectionmolding of a flexspline for a plastic harmonic drive, which has difficulty in cavity filling because its minimum thickness is only 0.35 mm. The induction heating is then successfully implemented on the ultra-thin wall molding by raising the mold surface temperature around the glass transition temperature of the molding material.



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Theoretical Background of Induction Heating



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SummaryThe high-frequency induction heating can rapidlyheat the mold surface prior to the injection stage, such that a hot mold cavity can be obtained. In order to investigate the high-frequency induction heating process, a coupled finite element analysis of electromagnetic field and transient heat transfer was carried out. Through the comparison of the CAE analysis with experimental measurements, it was shown that we could rapidly heat only the mold surface, not to raise the temperature of the entire mold. Induction heating was applied to injection molding of the thin-walled part with micro-teeth profile. It only took 1.5s to raise the mold surface temperature up to 190°C by induction heating, so that we could completely filled out the micro-teeth without a significant increase of the cycle time.


NEW TECHNOLOGY TO VARY THE RADIAL THICKNESSDISTRIBUTION OF THE PARISON IN EXTRUSION BLOW MOULDING

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AbstractThe optimum parison shows thickness changes over the length and over the circumference to mach thedifferent draw ratios in the final blown part. The thickness variations in direction of the length can be easily achieved by moving the conical mandrel. Now a new technique is available to also dynamically profile the thickness of the parison over the circumference. It can be applied for all die diameters. In many cases the technique can even be easily retrofitted to existing dies to reduce material consumption.The details of the technology will be explained and resultsachieved as well on pilot machines as also on productionmachines will be presented.



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CONTROLLING DIMENSIONS WHEN INJECTION MOLDING MICROFLUIDIC DEVICES

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AbstractTo evaluate the ability to maintain the dimensions ofthe microfluidic channels during manufacturing,polystyrene, polycarbonate and PMMA were molded usingelectroformed nickel tooling. Melt and mold temperature,flow direction (i.e., impingement and parallel flow),backing material for the tooling, and vacuum venting weresystematically varied to determine their effects on channeldepths and widths. Replication of channel depths dependedon melt viscosity and was enhanced by mold and melttemperature, but replication of channel widths depended oncooling and the ability fill the channels. Impingement flowprovided better replication of channels widths. Backingmaterial and vacuum venting had no effect on replication.



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Effect of Cavity Pressure Profile on the Cellular Morphology of Injection-Molded HDPE Structural Foams

Extensive experiments were conducted in Advanced Structural Foam Molding using HDPE and nitrogen (N2) with 3 variables: the N2 content, the void fraction, and the injection speed. During processing, the cavity pressureswere measured and recorded using the data acquisition (DAQ) system in order to help understand the foaming mechanisms in structural foam molding. The injection molded HDPE structural foams were characterized in termsof cross-sectional foam morphology and void fraction. The experimental results were then interpreted with respect to the cavity pressure profiles obtained from each processing condition.


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Development of Gas-Assisted Dynamic Mold Temperature Control System and Its Application for Micro Molding S.C., ChenDynamic mold surface temperature control (DMTC) has the advantage of improving molded part qualities without significant increases in cycle time. A gas-assistedheating system combined with coolant was developed to achieve DMTC for injection molding. With gas-assisted heating, it takes 2 seconds for the mold surfacetemperature to vary from 60C to 120C whereas it requires 186 sec using coolant heating. Further, it takes 21 sec and 84 sec for the mold surface to cool to 60C under gas heating and coolant heating, respectively. The gas-assisted heating system also shows excellent efficiency for micro injection molding of biochips to achieve high replicationaccuracy of the micro channels.


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Development of Gas-Assisted Dynamic Mold Temperature Control System and Its Application for Micro Molding S.C., Chen


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HOT EMBOSSING OF DISCRETE MICROPARTS

D.G. Yao

Hot embossing is a widely used technique in polymer micro fabrication. The main advantage of hot embossing over micro injection molding is its simple tool and process setup. However, hot embossing has so far being mainly developed for replication of surface structures on thermoplastic substrates. Because of the lack of a through thickness action, fabrication of micro parts such asmicrogears is considered difficult. In this study, an embossing mold having 49 micro cavities was used in a through-thickness embossing process. Microparts made of HDPE with each part weighing approximately 1.2 mg were successfully embossed. When in the mold, embossed microparts were connected to each other through thin residual films of a thickness less than 10 µm on both sides. The residual films were detached from the microparts during ejection. Because no resin delivery path, e.g., runner and gate, is needed for microcavities on the mold, this micropart fabrication process could replace micro injection molding in numerous applications.


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HOT EMBOSSING OF DISCRETE MICROPARTS D.G. Yao


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D.G. Yao


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D.G. Yao


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HOT EMBOSSING WITH AN ENLARGED PROCESS WINDOW

D.G. Yao


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HOT EMBOSSING WITH AN ENLARGED PROCESS WINDOW

D.G. Yao


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HOT EMBOSSING OF HIGH ASPECT RATIO SUB-m STRUCTURED SURFACES FOR MICRO FLUIDIC APPLICATIONS

Sub-micro structured surfaces allow modifying the behavior of polymer films or components. Especially in micro fluidics a lotus-like characteristic is requested for many applications. Structure details with a high aspect ratio are necessary to decouple the bottom and the top of the functional layer. Unlike to stochastic methods patterning, with a LIGA-mold insert it is possible to structure surfaces very uniformly or even with controlled variations (e.g. with gradients). In this paper we present the process chain to realize polymer sub-micro structures with minimum lateral feature size of 400 nm and up to 4 (m high).


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Documents

ANTEC 2008射出成形發展趨勢 · acquisition of the molding process was conducted using a CCD (Charged-Coupled Device) camera. It was found that the flow hesitation is dependent