US3525282A

US3525282A - Spinneret punching tool

Info

Publication number: US3525282A
Application number: US696878A
Authority: US
Inventors: Curtis Owen Hawkins
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1968-01-10
Filing date: 1968-01-10
Publication date: 1970-08-25
Anticipated expiration: 1987-08-25

Description

United States Patent w13,52s,2s2

[56] References Cited UNlTED STATES PATENTS 3,017,789 1/1962 Cobb 72/334 3,174,364 3/1965 Sims 76/107 3,187,607 6/1965 Krummeck 76/ 107 Primary Examiner- James M. Meister An0rney Howard P. West, Jr.

ABSTRACT: A punch tool for single step forming a complex spinneret orifice having a plurality of segmented slot configurations is made in two parts and assembled. The tool includes a body member having die segments formed on one end corresponding to the inner portion of the slot configuration and a sleeve fitted over the body member. Finish-machining the punch to the precise configuration desired is accomplished after assembly.

:- III b Patented Aug. 25, 1970 3,525,282.

INVENTOR CURTIS OWEN HAWKINS BY oaidlcd ATTORNEY SPINNERET PUNCI-IING TOOL BACKGROUND OF THE INVENTION This invention relates generally to spinnerets used for spinning viscous organic materials into filaments, and more particularly to the fabrication of spinneret capillaries which are used to produce muIti-void hollow filaments. Spinneret capillaries used to form multi-void hollow filaments by coalescing below the face of the spinneret require complex orifices on the face of the spinneret. These complex orifices are made up of a number of short, shaped slots arranged in a pattern. The outer shape of the spun filament is formed by segments of an outer configuration. This portion is segmented to provide points where air can enter the formed voids to prevent collapsing of the filament and to provide metal support to the internal sections forming the complex orifice. Internal arms join the segments of the outer configuration. These arms supply the polymer which form the partitions between the voids in the hollow filaments.

To obtain good filaments, it is absolutely essential that the complete orifice for each capillary be made precisely and that all the orifices in a spinneret be identical. One approach, described in US. Pat. No. 3,174,364, uses shaped inserts in a single hole. The approach is costly and tedious. Another approach is disclosed in US. Pat. No. 3,187,607. Here complex, multiple-segment orifices are formed by using a punch with a relatively simple shape and indexing the punch into several positions. This also is tedious and time consuming.

It would be preferable to be able to form the complex, multi-segment, orifice with a single punch in one operation. However, it is practically impossible to machine a punch from a single piece of material to the precision and accuracy required. Frequently, the largest dimension of the outer configuration enclosing the complex orifice is only 0.050 to 0.100" and the width of the slots is between 0.002 and 0.005". Removing metal at the intersection of an internal arm with an outer segment to form a male punch is very difficult in the sizes involved and still obtain a precise and sharp intersection.

SUMMARY OF THE INVENTION Therefore it is an object of this invention to provide a punch tool for single step forming a complex spinneret orifice having a plurality of segmented slot configurations formed from outer and inner slots arranged in a desired pattern. The method of making the tool is also a part of this invention. The punch tool includes a body member, on one end of which are formed male die segments corresponding to the inner slots, and a sleeve, having one end shaped to correspond to the outer slots. The sleeve is fitted over the formed end of the body member and is internally sized to provide a tight fit on the body member. After the sleeve is assembled on the body member it is finish machined to obtain the precise configuration required.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a fragmentary bottom view of a spinneret plate showing a complex multi-segment orifice;

FIG. 2 is an end view of the male punch of this invention;

FIG. 3 is a partial sectional view, taken on lines 3-3, of FIG. 2,and;

FIGS. 4, 5, 6 and 7 illustrate other discharge orifice configurations that can be made with the improved punch of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Shown in FIG. 1 is a fragment of a spinneret plate with one complete orifice 12. Orifice 12 is made up of three segmented

slot configurations

14, 16 and 18 with

internal slot arms

20, 22 and 24.

Webs

26, 28 and 30 support the internal portion of the plate enclosed by the outer configuration made up of slot segments l4, l6 and 18.

The male tool used to punch orifice 12 is shown in FIGS. 2 and 3. Punch '32 is made up of body 34 and sleeve 36. Body member 34 includes a reduced diameter portion on one end that terminatesin a shoulder 39. Web-like

male die segments

38, 40, 42 are machined in the reduced diameter end portion of body 34 to correspond to the internal slot arms, 20, 22, 24 and extend radially outward from central recess 31 in the end of the body member.

Sleeve 36 is machined, i.e. internally sized, so that it has a force fit over the reduced diameter portion of body member 34. Sleeve 36 is then pressed on body 34 until it abuts shoulder 39, then the tip of the sleeve is finish machined, forming

surfaces

35 and 37 which converge to form cutting edge 33 that is flush with the end of body member 34. Surface 35 is interrupted at each male die segment to form a precise matching extension for the male die segments e.g. extension 43 (FIG. 2) abutting male die segment 42. Notches 44, 46 and 48 are machined to permit

webs

26, 28 and 30 to remain in orifice 12. The punch is then hardened. The male punch tool of this invention can be used in the spinneret production method described in US. Pat. No. 3,017,789. An entrance hole is made from the backside of the spinneret plate, ending in a flat bottom counterbore. Usually about 0.012 inch of material is left between the bottom of the counterbore and the face of the spinneret. The diameter of body 34 is usually the same as the I diameter of the counterbore so that the walls of the counterbore serve as a guide during the punching step. Punch 32 is inserted into the counterbore and the punching step performed." After punching, a protuberance remains on the face of the spinneret. On removal of this protuberance, an orifice essentially like orifice 12 is formed. Broaching tools can be used to size the segments and the arms in separate broaching operations if desired; or a single male tool similar to the punch described above can be used to broach the whole complex orifice in a single sizing step.

Punch 32 provides a simple and relatively inexpensive means of forming orifice 12 with a single punching step. To do this, it is essential that the working end of the punch be precise and accurate. Of great importance is the intersection between the sleeve surface and the male die segments. In addition, any variation or inaccuracy between the relative parts would cause poor product.

While this invention has been described with respect to a threesegment orifice, it should be obvious that it could be used with a four-segment orifice, such as illustrated in FIG. 4. It is, of course, obvious that the outer configuration does not have to be a pure circle such as that in FIGS. 1 and 4 but can be any other configuration. Other exemplary configurations with non-circular outer configurations are shown in FIGS. 5 and 6; It is not necessary for all segments of the outer configurationsto have internal arms, nor for the segments to be the same size. FIG. 7 illustrates such an orifice, which can be made by the tool of this invention.

While I have described my invention with regard to a male punching tool, it should be obvious to one knowledgeable in this art, that my invention can be used equally, with. advantage, in making complex-shaped broaches.

It is apparent that many widely different embodiments of this invention can be made without departing from the spirit and scope thereof; and, therefore, it is not intended to be limited except as indicated in the appended claims.

I claim:

1. A punch tool for forming a complex spinneret orifice having a plurality of segmented slot configurations said configurations having outer and inner portions, said tool comprising:

a. an an elongated body member having a plurality of male die segments formed in one end, said die segments being formed to correspond to said inner portions; and

b. a sleeve fitted over said one end, said sleeve having a shaped cutting end corresponding to said outer portions, said sleeve being internally sized to provide a tight .engaging fit on said body member, said shaped end being flush with said one end.

b. a sleeve fitted over said one end, said sleeve having a shaped end corresponding to said outer portions, said sleeve having internal extensions engaging said male die segments, said shaped end being flush with said one end.

3. The apparatus of claim 1 wherein said male die segments extend radially from a central recess in said one end.