Operator tooling for the Touch-up Procedure

Transcription

1 Operator tooling for the Touch-up Procedure Current State Current Process: After the printing process is complete part of the gold ink is not connected and the operator is required to touch-up this portion of the part. The tool used has a toothpick or needle like point and a handle similar to a pencil. The distance between the painted part and the location of the operator's hand requires the tool to be long, or requires the operator to hold the far upper end of the tool so that the point can reach the part. Problem: The tool is not comfortable to hold and use repeatedly all day. The necessary positioning of the hand and arm to perform the touch-up is uncomfortable. The risk factors for the micro pen operators are repetitive hand and arm motions in unsupported, awkward postures. The exposure is in combination with contact stress from grasping tools while applying force, and applied contact stress from the sharp bench edges. The touch up process require operators to lean forward and assume static postures of the arm, neck and torso for extended periods. Research Static postures are positions that are held for extended periods. Static postures increase loads or forces on the muscles and tendons needed to maintain those postures, which contributes to fatigue. Fatigue is a precursor to WMSDs. Muscles require movement in order to allow blood flow. Blood flow brings nutrients to the muscles and carries away the waste products of muscle metabolism. (2) The current workstations, prevents the workers from working in a neutral posture. Due to the lack of legroom at the workstation the operators are forced to sit sideways adapting an awkward posture to complete the process. Working in an awkward posture can restrict blood flood and cause the employee to exert more effort to perform a task than working in a neutral position. The neutral posture is the optimal position of the body to exert the greatest force, promote blood flow and nerve conduction and reduce the risk of ergonomics related injury. (2) Future State Objective: To avoid awkward postures of the hand and arm as well as to prevent the operator from experiencing excessive exertion and strain while performing the touch up process. Steady movements and high accuracy instrument manipulation are also required. Suggested Process Improvement (Solution): Utilizing a mechanical fixture to hold/support the tool during the touch up process provides more control than moving the tool by hand. The Mechanical fixture gives the operator a stable performance while simultaneously providing flexibility and maneuverability, enabling the operator to manipulate tooling with precision. Keeps wrist in a neutral position (straight wrist). Reduce awkward elbow and shoulder postures. handles made of slip-resistant materials Increase handle diameter Less effort or rotational movement to use Reduce Touch up time and time spent holding tool. Small, flexible joints for precise positioning. Matches the operator s hand movements. Lateral tooling movements are inverted by the pivoting point and can be scaled depending on the tool insertion depth.

2 Option 1: Touch up Tooling Clip (Pen Clamp) Overview: This idea is a clamp that would be placed within the operator s field of view while doing the touch up procedure. This idea was in response to the issue of being able to find your tool when starting the touch up procedure. Steps for Fabrication/Purchase: N/A Cost to Implement: N/A Figure 1: This is a rough sketch of what the clamp would look like, it would be plastic / able to deform Figure 2: This is what it would look like holding the tooling

3 Option 2: Slotted Touch up Tooling Fixture Overview: Steps for Fabrication/Purchase: N/A Cost to Implement: N/A Figure 3: 2D Touch Up assist tooling. Tool tip modification may be required for functional implementation.

4 Option 3: Steady Hand Tooling Arm Fixture Based on Da-Vinci-Surgical-System Overview: This option was created based on the Master controls located in the surgeon console of the Vinvi Surgical system. Using the da Vinci Surgical System, the surgeon operates seated comfortably at a console while viewing a high definition, 3D image inside the patient s body. The surgeon's fingers grasp the master controls below the display with hands and wrists naturally positioned relative to his or her eyes - The system seamlessly translates the surgeon's hand, wrist and finger movements into precise, real-time movements of surgical instruments (3) i. Range of movement is not constrained ii. Many subassemblies (Components and Joints)

5 Option 4: Steady Hand Tooling Arm Fixture Overview: Developed by benchmarking surgical guided robotic systems (MazorRobotics, MAKOplasty, Transbuccal system, Da-Vinc Robotic Arm and Tilo Wüsthoff DLR MIRO). Using a fixture to help support and stabilize the tooling dramatically increases the precision and accuracy of the operator. i. Range of movement is not constrained ii. Comparable to the movement capable of a human arm. iii. Requires Less Material than Option 3 (Components and Joints) Figure 1: The seven degrees of freedom of the open kinematic chain allow the systems to inherent motion resembling the actions performed by the operator. Using a cylinder connection to hold the touch up tool lets the tooling rotate around the single axis, this may be useful when cleaning the tip of the tooling.

6 Option 5: Steady Hand Tooling Fixture With Constrained Ranges i. Range of motion or movement of tooling fixture constrained ii. Requires fewer moveable parts than Option 4 (Components and Joints) Figure 2: Pin connection can rotate the tooling about an axis (forward and backwards) Figure 4: Rails allow the subassembly to translate the along the selected axis. Moving the tip of the touch up tool close to the cliff of the probe Figure 3: Rotating the tip side to side

7 Option 6: Simplified Steady Hand Tooling Fixture with Constrained Ranges i. Range of motion or movement of tooling fixture constrained ii. The fewest number of moveable parts (Components and Joints) without constraining the operator Figure 5: By guiding the tooling fixture sub assembly, the system becomes a slave device that is exactly constrained to preferred path of the touch up tool Figure 6: A Ball Joint possess zero translational degrees of freedom. Therefore, rails are used to facilitate the linear translation of the tooling fixture sub assembly. Two rails permit precise positioning of the subassembly along the selected axis without allowing rotation. Figure 8: A ball joint possesses three rotational degrees of freedom. This Allows for smooth motion to maintain precision alignment and handling of the touch up tool. The ball joint can be heat treated, have lubricated fittings and coated with Teflon, to enhance endurance and increase component life. Figure 7: Range of motion is constrained to the desire dimensions required to perform the touch up. Simple way to limited rotation angles and range of motion.

8 Tooling Extension: Figure 4: Simple handle attached to the end of the touch up tooling Figure 5: Attached handle is adjustable for operator s preference in angle Figure 7: Manipulate position using an attached touch up tool located closer to the operator

9 Test Types Description Pass criteria Units Stress test Passes within factor of safety PSI Endurance Test Doesn t fail after continuous use Cycles/hour Operator Survey Reduces Ergonomic Stresses Percentage (yes / no) Workstation Test Ranges based on ER cm Ergonomic Test Range based on ER Degrees Stress Tests: 1. Find factor of safety, Test until failure 2. Analyze the system with average operator load ~20N (overestimate) Deflection of Fixture, ensure that the deflection doesn t Interfere with the process Bending Stress at Base Life expectancy of ball joint and rails 1. The Workplace Safety and Health Council. "Workplace Safety and Health Guidelines Improving Ergonomics in the Workplace." Wshc. Workplace Safety and Health Council in Collaboration with the Ministry of Manpower., Jan Web. 6 Nov < ovingergonomicsintheworkplace.pdf> "The Da Vinci Surgical System." Intuitive Surgical. N.p., n.d. Web. 24 Nov < 4. "Spine & Brain Renaissance Guidance System Mazor Robotics." Mazor Robotics Renaissance Guidance System Home Comments. N.p., n.d. Web. 24 Nov <