# US 2018/0021827 A1 · Method of manufacturing boron coated straws for neutron detection through spiral winding and welding

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2018/0021827 A1
- Document ID: US20180021827A1
- Status: Published application
- Kind: A1
- Application number: 15/603,233
- Filed: 2017-05-23
- Published: 2018-01-25
- Earliest claimed: 2016-05-23
- Assignees: Proportional Technologies, Inc.
- Applicants: Proportional Technologies, Inc.
- Inventors: Jeffrey L. Lacy
- Web page: https://patentgrep.com/patent/US20180021827A1

## CPC

- B21C 37/122: {with welded or soldered seams}
- B21C 37/126: {Supply, or operations combined with supply, of strip material}
- B23K 26/0823: {Devices involving rotation of the workpiece}
- B23K 26/0838: {by using an endless conveyor belt}
- B23K 26/0884: {in at least three axial directions, e.g. manipulators, robots}
- B23K 26/30: of three-dimensional [3D] seams
- B23K 26/322: involving coated metal parts (using absorbing layers on the workpiece B23K26/18)
- G01T 3/00: Measuring neutron radiation (G01T5/00 takes precedence)
- B23K 2101/34: Coated articles {; Surface treated articles}
- B23K 2101/36: Electric or electronic devices
- B23K 2103/08: Non-ferrous metals or alloys
- B23K 2103/166: {Multilayered materials}
- B21C: MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)

## Abstract

A method and apparatus are disclosed with a continuous straw forming process for spiral winding boron-coated foil into a rounded tube or cylinder with an overlap and tight contact between the spiral edges, and a welding process utilizing a high precision fiber laser to weld the spiral seem forming a straw tube.

## Claims

### Claim 1

An improved process for forming boron coated straws for use in neutron detectors comprising the steps of:
providing a reel of boron-coated film, a fixed, elongated mandrel having an outside diameter approximately equal to the desired inside diameter of the straws to be formed; and a laser welding system;
spiral winding the boron-coated film around the elongated mandrel such that the boron-coating is adjacent to the mandrel and the outside edges of each wind of film overlaps the previous wind by no more than about 1 millimeter;
rotating the spirally wound and overlapping film about the mandrel and advancing the film down the mandrel;
welding the overlapped edge of the spirally wound film to form a seam using a laser welding system as the film advances down the mandrel thereby creating a cylinder; and
cutting the cylinder to a desired length thereby forming a boron-coated straw.

### Claim 2 (depends on 1)

The process of claim 1 further comprising the steps of:
providing a guide pin having beveled guides on each end, the length of the guide pin being approximately equal to the width of the film; and
guiding the film through the guide pin before spirally winding around the mandrel to ensure consistent overlap of the film.

### Claim 3 (depends on 1)

The process of claim 1, further comprising the steps of:
providing a belt drive system comprising at least one belt and two motor driven capstans;
wrapping the belt around the mandrel on top of the overlapped foil; and
rotating the belt using the motor driven capstans to rotate and advance the spiral wound film.

### Claim 4 (depends on 1)

The process of claim 1, wherein the spiral winding step leaves an overlap of the film edges of no more than about 0.5 millimeters.

### Claim 5 (depends on 1)

The process of claim 1 wherein the laser welding system provided comprises a YAG fiber laser.

### Claim 6 (depends on 1)

The process of claim 1 wherein the welding step comprises welding by continuously using spot welds of about 25 μm.

### Claim 7 (depends on 1)

The process of claim 1 wherein the laser welding system provided allows 3-axis motion for moving a laser welding head.

### Claim 8 (depends on 1)

The process of claim 1 further comprising the steps of:
providing a laser velocimeter; and
measuring the speed at which the newly formed cylinder advances down the mandrel with the laser velocimeter.

### Claim 9 (depends on 4)

The process of claim 4 further comprising the step of:
using the speed measurement to determine the proper time to cut the cylinder to achieve the desired length of the straw.

### Claim 10 (depends on 5)

The process of claim 5 wherein the cutting the cylinder step occurs at the proper time determined using the speed measurement.

### Claim 11 (depends on 1)

The process of claim 1 wherein the cutting step comprises cutting the cylinder with a scissor mechanism.

### Claim 12

An improved continuous process for forming boron coated straws for use in neutron detectors comprising the steps of:
providing a reel of boron-coated film, an elongated mandrel having an outside diameter approximately equal to the desired inside diameter of the straws to be formed, a belt drive system comprising at least one belt and two motor driven capstans, a laser welding system, a laser velocimeter, and a scissor mechanism for cutting;
spiral winding the boron-coated film around the elongated mandrel such that the boron-coating is adjacent to the mandrel and the outside edge of each wind of film overlaps the previous wind by no more than about 0.5 millimeter;
maintaining a tension on the film reel to ensure a forcible backwards pull on the film as it wraps around the mandrel;
wrapping the belt around the mandrel on top of the overlapped foil;
rotating the belt using the motor driven capstans to rotate and translate the spirally wound and overlapping film down the mandrel;
welding the overlapped edge of the spirally wound film to form a seam using a laser welding system as the film advances down the mandrel thereby creating a cylinder;
measuring the speed at which the newly formed cylinder advances down the mandrel with the laser velocimeter
using the speed measurement to determine the proper time to cut the cylinder to achieve the desired length; and
cutting the cylinder with a scissor mechanism at the determined proper time thereby forming a boron-coated straw of the desired length.

### Claim 13 (depends on 12)

The process of claim 12, further comprising the steps of:
providing a guide pin having beveled guides on each end, the length of the guide pin being approximately equal to the width of the film; and
guiding the film through the guide pin before spirally winding around the mandrel to ensure consistent overlap of the film.

### Claim 14 (depends on 12)

The process of claim 12 wherein the laser welding system provided comprises a YAG fiber laser.

### Claim 15 (depends on 12)

The process of claim 12 wherein the welding step comprises welding by continuously using spot welds of about 25 μm.

### Claim 16 (depends on 12)

The process of claim 12 wherein the laser welding system provided allows 3-axis motion for moving a laser welding head.

### Claim 17

An improved apparatus for forming boron coated straws for use in neutron detectors comprising:
a reel of boron-coated film, the film having a width;
a fixed, elongated mandrel, the mandrel being positioned such that as the boron-coated film is drawn off the reel, it will spirally wrap around the mandrel with an overlap;
a guide pin having beveled guides at each end with a width approximately equal to the film width, the guide pin guiding setting a consistent overlap of the film as it spiral wraps around the mandrel;
a belt drive system comprising at least one belt and two motor driven capstans, the belt drive system rotating the film to spirally wrap the film about the mandrel and translating film along the fixed, elongated mandrel;
a microscopic fiber laser for welding a seam formed at the overlap of the spirally wound film as the film rotates and translates, thereby forming a cylinder;
a laser velocimeter for measuring the speed at which the cylinder; and
a scissor mechanism for cutting the cylinder at the desired length.

### Claim 18 (depends on 17)

The apparatus of claim 17, wherein the microscopic fiber laser comprises a YAG fiber laser.

### Claim 19 (depends on 17)

The apparatus of claim 17, further comprising a tension motor for maintaining tension on the film as it is drawn out of the reel.

### Claim 20 (depends on 17)

The apparatus of claim 17, wherein the microscopic fiber laser comprises laser head that is automatically controlled for movement along 3 axes.