Straight Shot® Hot Sprue Bushings S-Series Straight Shot
79
Larger Shots – Extended Heater Life DME developed Straight Shot Hot Sprue Bushings to eliminate sprues, permit larger shots and faster fills, and greatly extend heater life. The bushings feature an unrestricted “straight-shot” channel to feed the part or runner. Material in the channel is heated by a special helical tubular heater which surrounds the melt stream. This heater distributes heat uniformly throughout the bushing and is virtually impervious to moisture, gases and plastics contamination.
The helical tubular heater (120 or 240 volt) is thermocouple equipped so temperature can be closely controlled using a DME single-zone Closed Loop Temperature Controller. The standard S-Series Straight Shot is designed for direct part gating or for feeding half-round or trapezoidal runners. It is supplied with a .16 diameter gate and no gate land. Available in seven standard shoulder lengths with either a 1 ⁄ 2 " or 3 ⁄ 4 " s pherical radius and 120 or 240 volt heater. The S-Series Straight Shot can be retrofitted to almost any mold that uses a conventional sprue bushing.
5.09
1.995 DIA. +.000 –.005
7 TO 3
A =
7
.19
8
8
U.S. Patent No. 4,273,525
.19
.16 DIA.
1.000 DIA.
.31 DIA.
R
WITH 240 VOLT HEATER ITEM NUMBER
SHOULDER LENGTH A
R
.015 RELIEF
.015 RELIEF
.340
.62
1 7 ⁄ 2 3 ⁄
SSBT4517S2 SSBT4523S2
1 ⁄
8
Replacement Cores
2
8
NOTE: 5° heater lead is standard. For 90° lead, add “90” to end of item number (e.g., SSBT4517S290).
IEM NUMBER
SPH.RAD.
SSBT45 SSBT65
.500 .750
NOTE: The expansion factor must be taken into consideration prior to machining for and installation of the bushing. This factor (BE) must then be added to the A dimension. The formula for determining this expansion factor is as follows: BE = “A” dimension x 0.00000633 x nozzle set point - 68ºF (assuming the mold is at 68ºF during operation). If mold temperature is different, substitute 68ºF with actual mold temperature.
Typical Applications
EXAMPLE: Given a setpoint of 500°F:
BE = 1.375 × .0000063 × (500 – 68) = .004 thus 1.375 + .004 = 1.379. Please note that the above information is given as an example. Variations may occur based on mold configuration and cooling factor. In some instances, it may be necessary to obtain an empirical factor.
FEEDING A TRAPEZOIDAL RUNNER
DIRECT PART GATING
U.S. 800-626-6653 n Canada 800-387-6600 n DME.net n store.DME.net
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