Scope: Mold shrinkage is the shrinkage of the polymer as it cools after the molding process. It is typically used to properly machine injection molds so that final. Purchase your copy of ASTM D – 08() as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards. Buy ASTM D R TEST METHOD OF MEASURING SHRINKAGE FROM MOLD DIMENSIONS OF THERMOPLASTICS from SAI.
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ASTM D – Standard Test Method of Measuring Shrinkage from Mold Dimensions of Thermoplastics
Start Webshop Product catalog Product d9555-08. As the cooling rate of the material is proportional to the square of the reciprocal of the thickness, the minimum cooling time for the cavity can be expected to be close to 1. The values given in parentheses are given for information only. If you need to be able to add standards to the monitoring service, you must register as a user with your own username and password. Three qstm warp is dened as 3 mm depth deection, positive or negative, per mm in length.
It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Mold shrinkage is calculated as inches per inch or percent or mm per mm for the specified dimensions and conditions. Current edition approved Nov. D955-80 such as mold and melt temperature, fill times, and packing conditions are known to affect shrinkage significantly.
Thus the mass of material injected into the cavity is not clearly dened and the orientation of the material near the gate will be perturbed. If the document is revised or amended, you will be notified by email. Adherence to the specied mold design see 7.
Pressure transducers for monitoring the pressure in at least one cavity are mandatory for Type D2. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Each material was supplied in granular form to each of the testing laboratories by a single supplier. Link to Active This link will always route to the current Active version of the standard. It is the intent of this method to control and document as many of these variables as possible. Standards monitoring is a free service designed for you who wish to be alerted of changes to or new editions of the standards required in your work. Pressure transducers are recommended, but not mandatory for specimens Type A and Type B.
Injection Molds Digital micrometers Digital calipers Weighted digital drop gauge. Read more about subscriptions. Historical Version s – view previous versions of standard. The decrease in the cavity pressure at hold to zero indicates that the material in the gate has solidied sufficiently to stop ow into the cavity. Adherence to the specified mold design see 7.
Each laboratory obtained one test result for each material. Factors such as mold and melt temperature, ll times, and packing conditions are known to affect shrinkage signicantly. Do not modify or alter the edges used for the measurement of dimensions. Need more than one copy?
ASTM D955 – 08(2014)
The molding is done by an approved outside source. The principles of A number in parentheses indicates the year of last reapproval. It is typically used to asgm machine injection molds so that final part dimensions are as desired.
You can download and open this file to your own computer but DRM prevents opening this file on another computer, including a networked server. This ensures that you are always up-to-date and saves you both time and money. At point R, the value of the cav ity pressure at hold is recorded.
The length or diameter of the cavity is measured depending on shape of mold. The minimum hold time can be read from the decrease of the cavity pressure to zero. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. As the voice of the U. Originally approved in Intertek PTL molds for a 5″ x 5″ x 0. The temperature of the heating cylinder and the mold shall be maintained at a point which, d9955-08 a cycle selected, will produce temperature within the range recommended by the material molding standard.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which aatm may attend. It is recommended to cool specimens in a horizontal position at room temperature by placing them on a material of low thermal conductivity to minimize warpage.
Test specimens are molded under specified conditions. A superscript epsilon indicates an editorial change since the last revision or reapproval. This standard and Ashm are equivalent in the design of specimen D2. The data in Tables should not be rigorously applied to acceptance or rejected of material, as those data are specic to the round robin and may not be representative of other lots, conditions, materials, or laboratories. The thickness shall be 3. Subscription pricing is determined by: It would be incorrect to assume values form Tables for any new material.
Signicance and Use 5. The mold shall have at one end a gate 6.
Calculation and Report This standard is not included in any packages. Your Alert Profile lists the documents that will be monitored. Values would not be expected to be in agreement with those obtained using the specimens described in 8.