MOLD COOLING Heat Pipes - Cooling Pins
MOLD COOLING Heat Pipes - Cooling Pins Reduce Maintenance and Operating Costs The increased waterline diameter, coolant velocity and heat capacity effectively eliminate scale formation, calcium deposits and the plugging up of small waterlines and ports. In addition, Heat Pipes operate in any coolant without corroding. Upgrade Existing Molds and Dies Heat Pipes effectively solve cooling, cycle time or part quality problems in existing molds. They can be retrofitted as replacements for bubblers or baffles and to provide heat transfer in previously uncooled areas. Salvage Damaged Molds and Dies In certain applications, Heat Pipes can even be used to salvage or repair molds that would otherwise have to be scrapped or extensively reworked.
TPL and TPH heat pipes for injection molding For low-temperature Heat Pipes (40˚-200˚F) use TPL (color- coded BLACK) as a prefix in front of item number in the chart below. For high-temperature Heat Pipes (150˚-400˚F) use TPH (color-coded WHITE) as the prefix. Examples: TPL8600; TPH6500.
How and where heat pipes work The DME Heat Pipe is a heat transfer device specifically designed for optimal performance in plastic injection molds. It consists of a vacuum-tight copper tube containing a wick and a non-toxic working fluid. One end of the heat pipe is an evaporator, the opposite end is a condenser. Thermal energy is gathered at the evaporator end, vaporizing the working fluid. This vapor then travels through the Heat Pipe to the condenser end. At the condenser end the vapor condensates back into a liquid, giving up its latent heat in the process. To complete the cycle the condensed liquid then travels along the wick, via capillary action, back to the evaporator section. This process repeats itself continuously, transferring heat many times faster than pure copper. How heat pipes are used Available in a variety of standard lengths and diameters, DME Heat Pipes are used in cores, core slides, cavities and other areas of a mold or die requiring cooling or controlled temperatures. Commonly used in place of bubblers, baffles, fountains or blades, Heat Pipes transfer heat rapidly to the coolant, rather than requiring the coolant to flow into the heated area. They are also used to transfer heat to a cooler portion of the mold (which serves as a heat sink) or to open air, thereby permitting cooling of otherwise inaccessible areas and eliminating potential coolant leakage.
TPL & TPH DIAMETER & ITEM NUMBER
LENGTH (INCHES)
1 ⁄
3 ⁄
1 ⁄
5 ⁄
3 ⁄
1 ⁄
8
16
4
16
8
2
3 4 5 6 7 8
4300 6300 8300 10300 12300 16300 4400 6400 8400 10400 12400 16400
4500 6500 8500
–
–
–
INTERNAL OPERATING TEMPERATURE OF HEAT PIPE
4600 6600 8600 10600 12600 16600
Benefits of heat pipes Cool Molds Faster and Reduce Cycle Time The Heat Pipe’s ability to cool molds faster and thus reduce cycle time is due to a number of factors. First, waterlines throughout the entire mold can be larger in diameter, permitting a higher coolant velocity, which transfers heat faster. Second, the larger volume of fluid flowing through the waterline results in a lower overall coolant temperature rise, so that the last Heat Pipe in the system will transfer heat as efficiently as the first. Third, the extension of the Heat Pipe into the waterline promotes turbulent flow, which transfers heat faster than laminar flow. Fourth, the ability to transfer heat away from inaccessible areas improves the overall cooling rate and reduces cycle time, even if extension into a remote waterline is impractical or impossible. Improve Part Quality As the Heat Pipe transfers heat to the coolant, air or mold component, it also dissipates heat evenly along its entire length. This isothermal action provides faster and more uniform cooling, thus eliminating hot spots, which cause sink marks, pulling and spotting. Simplify Mold Design and Lower Costs With Heat Pipes, waterline design is greatly simplified since coolant flow into the heated area of the mold is not required. In addition, the ability to locate heat conductors in areas inaccessible to other cooling devices can further simplify the overall mold design. In most cases, the machining and construction time required for the mold is reduced, lowering moldmaking costs. MAXIMIZING EFFICIENCY WITH WARM COOLANT Heat Pipes work best when the coolant is between 60° and 110°F, and sometimes higher. The graph illustrates how the Heat Pipe’s heat transfer capability is dependent upon its internal operating temperature. It is best to start with the coolant temperature high, then reduce it if necessary.
4700 6700 8700
–
–
–
4800 6800 8800 10800 12800 16800
10 12
– –
– –
– 101000 121000 161000
–
–
– 161200
WATER FLOW
Silver heat transfer compound* – HTC06S
A
ITEM NUMBER HTC06S
Contains micronic particles of silver to provide a thermal resistance of 4.75°C
in/watt. The compound is supplied in a 5cc plastic syringe. (DME recommends the Silver Heat Transfer Compound because it has eight times lower thermal resistance than the copper equivalent.) Copper heat transfer compound* – HTC30C
.125'' MIN
TAMP RINGS
EVAPORATOR END HEAT IN
CONDENSER END HEAT OUT
“O” RINGS
Selecting the right size and shape The standard diameters and lengths of TPL and TPH Series Heat Pipes will satisfy most applications.
LIQUID
VAPOR
TPL & TPH SERIES Diameter (O.D.)
TOLERANCES
±.004
Contains micronic particles of copper to provide a thermal resistance of 38°C in/watt. The compound is supplied in a 5cc plastic syringe.
ITEM NUMBER HTC30C
Length ±.020 NOTE: Heat Pipes cannot be used as ejector pins and parts cannot be molded or cast against them. Also, Heat Pipes cannot be cut, machined, bent or plated. If a special size is required, contact DME to discuss your application.
WICK
Standard injection molding heat pipes The standard line of Heat Pipes for injection molding includes both a low-temperature (TPL) and a high- temperature (TPH) series. The TPL Series works most efficiently between the temperatures of 40˚ and 200˚F with a coolant temperature of approximately 60˚ to 80˚F, and the TPH Series between 150˚ and 400˚F with a coolant temperature of approximately 90˚ to 110˚F. The sealed end of each heat conductor is color-coded (BLACK for the TPL series and WHITE for the TPH Series). Selection of the appropriate series is based on the application’s melt, mold surface and coolant temperatures to which the Heat Pipe will be subjected.
* For .125" diameter Heat Pipes, do not use applicator tube supplied with Heat Transfer Compound. Apply desired amount of compound directly into core hole.
Tamp ring sets – TARS Each set includes 32 silver alloy tamp rings (enough for installing 16 Heat Pipes) and one hollow tamping tube. Select the required tamp ring set by its I.D. to match the O.D. of the Heat Pipe being used.
TARS- 04
TARS- 06
TARS- 08
TARS- 10
TARS- 12
TARS- 16
ITEM NUMBER Ring I.D.
1 ⁄
3 ⁄
1 ⁄
5 ⁄
3 ⁄
1 ⁄
8
16
4
16
8
2
246
247
U.S. 800-626-6653 ■ Canada 800-387-6600 ■ www.dme.net ■ store.dme.net
U.S. 800-626-6653 ■ Canada 800-387-6600 ■ www.dme.net ■ store.dme.net
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