Design of a Tool for Creating Precise Cuts in Thin Wires
Design of a Tool for Creating Precise Cuts in Thin Wires from Dayana Hijaz
Design of a Tool for Creating Precise Cuts in Thin Wires

In undergrad, I was part of a research group that sought to evaluate the strength of barbed sutures. To do that, we wanted to run tensile test experiments using the university's Universal Tensile Test machine. The first experiments were done on a model of the barbed sutures that I had prepared. I chose a material that is easily accessible and closest in kind to that of suturing wires: 0.4 mm diameter nylon 6.6 fishing string. The challenge was to generate cuts of specific angles (150, 160, and 170 degrees) and depths of penetration (0.07, 0.12, 0.18 mm) to represent the barbed aspect of the sutures. In total, I had to create 9 different cuts in 4 mm diameter wires. To overcome this challenge I designed this tool to help me perform those very precise cuts.

The figure above is a side view drawing of a wire that was cut to create an anchor. The anchor models the barbed aspect of the barbed medical sutures. Notice the two dimensions that define the cut: the depth of cut and the angle of cut. There was 3 depths of cut studied: 0.07, 0.12, and 0.18 mm and three angles of cut studied: 150, 160, and 170 degrees, making a total of 9 different combinations of cuts. These cuts are to be generated on a 4 mm diameter wire.
The figure above shows the tool that I designed in Solidworks to generate the 9 different cuts. The tool consists of 5 parts all made of steel and manufactured on the CNC machine.
Looking at the front view, the bottom most part is the base. Notice 3 grooves of different depths. From left to right: 3.82, 3.88, and 3.93 mm corresponding to 0.18, 0.12, and 0.07 mm depth of cut in the wires. The groves are all based on a 4 mm diameter circle to fit the wire size. Looking at the left side view, there are three parts each having a plane of different angle: 10, 20, and 30 degrees. The tool will be used as following: the wires will be fitted inside the grooves. A cutting plane is chosen (let's say 10 degrees) and is screwed to the base part through 2 holes. The wires are fixed on the other side of the base using the 5th tool part which will also be screwed to the base through 2 holes. Finally, using a plane cutter which I slide along the cutting plane, I create three cuts of depth 0.07, 0.12 and 0.18 mm and angle 170 degrees. The process is repeated for the other two angles of cut.
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Design of a Tool for Creating Precise Cuts in Thin Wires

In undergrad, I was part of a research group that sought to evaluate the strength of barbed sutures. To do that, we wanted to run tensile test experiments using the university's Universal Tensile Test machine. The first experiments were done on a model of the barbed sutures that I had prepared. I chose a material that is easily accessible and closest in kind to that of suturing wires: 0.4 mm diameter nylon 6.6 fishing string. The challenge was to generate cuts of specific angles (150, 160, and 170 degrees) and depths of penetration (0.07, 0.12, 0.18 mm) to represent the barbed aspect of the sutures. In total, I had to create 9 different cuts in 4 mm diameter wires. To overcome this challenge I designed this tool to help me perform those very precise cuts.

Dayana Hijaz
ME Product Design Graduate at UC Berkeley Berkeley, CA