Die pin

A new nose eone was obtained and initial maehining performed by die repair faeility. The nose eone is supported by six radial pins. The nose eone and inlet easing were sent to die main plant to ensure die pin hole loeations were properly positioned. Here, die inlet easing was assembled and oversized pin holes were drilled and reamed in die pieees. Pins made to fit die holes were also maehined. Repau maehining... 

Mandrel (Torpedo) suspended in the center of the circular passage in the die body with metal bridges called spiders (typically three are used). One spider allows for passage of air into the center of the torpedo, is streamlined to avoid flow stagnation, and supports the die pin. 

Die land forms the outer diameter of the tubular extrudate, held in place with a retaining ring and position adjusted with centering bolts. The die land can be changed to create a tube of a different diameter or wall thickness while keeping the original die pin. 

Retaining plate secures the alignment of the die land with the die pin, bolted to the die body. 

Heater band closely fitted to the housing (and for larger pipes to the exposed portion of the die pin) to ensure that the die is held at a temperature close to the required temperature of the melt. 

Core tube mandrel with coat hanger-type passage that splits the flow and uniformly distributes melt along the annulus between the die pin and the die land. 

First, instead of passing air through the core tube, a bare conductor wire is pulled through the die entering the core tube inlet and exiting the die pin. 

Second, the length of the die pin is shortened to cause the wire to contact the melt tube before it exits the die land. 

Figure 6.11. Typical balance record at the surface tension measurement using die pin detachment mediod. AmaxF - force needed to detach the pin from the melt Wrem — mass of die remaining melt resting on the pin.

Uneven wall thickness circumferentially Pin not centered in die ring Adjust die pin position... 

Making a Pellet Using a KBr Handpress. Two methods are commonly used to prepare KBr pellets. The first method uses the handpress apparatus shown in Figure 25.5. Remove the die set from the storage container. Take extreme care to avoid scratching the polished surfaces of the die set. Place the anvil with the shorter die pin (lower anvil in Figure 25.5) on a bench. Slip the collar over the pin. Remove about one fourth of your KBr mixture with a spatula and transfer it into the collar. The powder may not cover the head of the pin completely, but do not be concerned about this. Place the anvil with the longer die pin into the collar so that the die pin comes into contact with the sample. Never press the die set unless it contains a sample. 

An alloy of molybdenum containing 1.2% hafnium with carbon at the level of 0.08—0.10% has a slight advantage over TZM. This alloy has been produced in small quantities for special extmsion dies and ejector pins in the isothermal forging of superalloys. 

Fig. 4. Pipe or tubing die for in-line extmsion A, die body B, mandrel, pin, and male die part C, die, die bushing, and female part D, die-retaining ring E, die-retaining bolt F, die-centered bolt G, spider leg H, air hole I, seat for breaker plate J, ring for attachment to extmder and K, die land (15).

The physical structures of microchip assemblies usually contain a number of thin films in contact, each of which plays a separate role in the performance of the device. As an example, in one structure a silicon thin film would be contacted on one face by a copper rod which conducts away die heat generated during computer operations, and on the other face by an aluminium thin film which acts as a connector to other silicon films. This aluminium film is in turn in contact with a ceramic layer containing other thin film devices, and widr copper pins which plug into the circuit board. 

As the final part of the repair proeess, the expander underwent a trial assembly at the repair faeility. The aetual job assembly and disassembly fixtures were used during the trial assembly. No signi-fieant problems were eneountered and internal elearanees were to speeifieations. As the assembly bed plate at the repair faeility did not exaetly duplieate the user s baseplate, there was some eoneern that readjustment would be required in the field to obtain elearanees. To faeilitate the field assembly proeess, appropriate pins and fixtures were manufaetured to hold axial and eoneentrie positions of the diffuser and stator as they were in die repair shop. The entire expander trial assembly was eompleted one mondi ahead of sehedule. 

TOP HOLD DOWN PINS TO INSURE MOULDING STAYS IN DIE WHEN PRESS OPENS... 

Basically the BM lines have an extruder with a die or an injection machine with a mold to form the parison or preform, respectively. In turn the hot parison or preform is located in a mold. Air pressure through a tubular pin-type device located usually at the parting line of the mold will expand the parison or preform to fit snugly inside their respective mold... 

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