Expertise
Descriptions, philosophies, and case studies on some subjects that Doven Design can provide expert support in.
Detailed and Functional 3D Models
With over 15 years of experience in SolidWorks and SolidWorks Simulation, Doven Design specializes in creating detailed and functional 3D models. Proficiencies range from designing simple machined parts to developing fully functional assemblies containing hundreds of components.
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3D Modeling and Assembly: Drafting intricate 3D parts and complex assemblies in SolidWorks, ensuring every design meets the highest standards of precision and functionality.
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Motion Studies: Conduct comprehensive motion studies to help clients visualize the movement and functionality of their designs, providing clear insights into the final product's performance.
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Finite Element Analysis (FEA): Utilize SolidWorks Simulation for FEA, employing stress plots during the design process to minimize stress concentrations and fatigue stress. This approach helps reduce weight and complexity while ensuring designs adhere to appropriate safety factors.
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Displacement Analysis: Leverage displacement plots to enhance consumer perception of quality, optimizing designs for both performance and aesthetic appeal.
Prototyping
Doven Design has prototyped a diverse range of products, leveraging various techniques such as 3D printing, laser cutting, waterjet cutting, sheet metal forming, CNC routing, CNC machining, cardboard modeling, and other basic modeling methods. Doven Design advocates for multiple stages of prototyping throughout the product development process, as nothing can replace the value [SD1] of physically evaluating a design. This hands-on approach ensures that designs are thoroughly vetted and optimized before moving to production, ultimately leading to better-performing and more reliable products. Below are some common processes used for prototyping.
Additive Manufacturing (3D Printing)
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Common Technologies: Fused Deposition Modeling (FDM) - Low Cost, Useful for rapid iteration early in the prototype process. Stereolithography (SLA) - Uses a photopolymer resin, useful for high-detail prototypes. Selective Laser Sintering (SLS) - uses powdered materials like Nylon, useful for strong functional parts with complex geometry. Cast Urethane - uses 3D printed mold, useful for simulating injection molded parts.
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Design Considerations: There are different attributes that should be considered when designing for 3D printing depending on the technology used and the part application. The strength of 3D printed material can vary depending on direction especially when printed in layers. For complex models, internal geometry supports must be considered in the design.
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Applications: 3D printed parts can successfully simulate machined, injection molded, and similar parts. Often multiple fixed parts can be 3D printed as one piece in a prototype.
CNC Cut Sheet Parts
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Common Technologies: Laser Cutting (Metals, Plastics, Woods), CNC routing(Plastics, Composites, Woods), Waterjet Cutting (composites, metals), Plasma Cutting (Thicker metals).
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Design Considerations: Cutter diameter must be considered when designing holes and internal geometry. Heating affected geometry from the cutting process should be considered. Some CNC cut processes require support or hold down geometry.
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Applications: CNC cut parts can successfully simulate stamped sheet metal parts and flat composites/woods in prototypes. Adding bending/welding/drilling/tapping operations adds to what you can use CNC cut parts for.
Machined Parts
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Common Technologies: Basic 3 axis up to 5 axis CNC machining, Manual 3 axis machining, Turning(Lathe), CNC Turning.
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Design Considerations: Cutter diameter must be considered when designing holes and internal geometry. Tool paths and fixturing must be considered, appropriate tolerancing for machine and process. Reducing complexity for prototype parts can reduce costs.
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Applications: Machined parts are often used for prototype and production parts. Complexity may be reduced for prototypes to enable use of a lower axis machine or a manual machine. Cost for one off machined prototype parts can be high. Machined parts are often used were precision and strength are important.
Off The Shelf Parts
During prototyping if standard off the shelf parts can be integrated into the design it can greatly reduce costs, time, and reliability.
Production Fixtures and Custom Test Equipment
Doven Design has extensive experience in designing and building fixtures for manufacturing, production testing, and engineering testing. The design process is guided by specific objectives and approaches to enhance precision, consistency, and efficiency while ensuring operator safety and reducing costs.
Manufacturing Fixtures
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Objectives: Enhance precision, consistency, and speed of production processes. Ensure operator safety and reduce costs.
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Approach: Focus on ergonomic design to minimize operator fatigue and error. Design fixtures to withstand long-term use and maintain reliability.
Production Test Fixtures
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Objectives: Ensure reliable and repeatable measurement of product attributes while minimizing impact on cycle times. Balance fixture cost and lifespan.
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Approach: Evaluate how fixtures will be used by operators to ensure processes can be repeated for extended periods without significant physical or mental fatigue. Minimize potential for operator error through thoughtful design. Use gauge R&R studies (repeatability and reproducibility) to validate the performance of fixtures directly related to measuring important features.
Engineering Test Fixtures
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Objectives: Design fixtures and equipment that provide precise control of all relevant variables, ensuring accurate and reliable test results.
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Approach: Follow the scientific process by controlling all possible variables to ensure successful engineering tests.
Product Troubleshooting, Root Cause Analysis, and Process Improvement
Case Study:
A client had persistent issues with a product losing calibration over time despite years of attempts to resolve the situation and improve product yield. Several steps including defining the problem, documenting as received condition of samples, FMEA, and controlled experimentation (isolating variables) were taken to identify the root cause of the non-conformance. Using root cause analysis, we first defined the problem (loss of calibration), then collected data by identifying and documenting the condition of samples received from the manufacturer. Then we ran controlled experiments, isolating variables, to identify the cause of the non-conformance.
In this case, the culprit was surprisingly simple: the wear of a plating/coating on a calibration screw. The calibration screw, with a rounded tip, interacted with the snap-action assembly through user input via a knob. Over time, the twisting action of the knob wore off the plating on the screw tip, effectively shortening the screw and causing calibration drift. This was determined by defining all plausible causes of the problem for each component and the interactions between each component.
No one had previously considered that user input could be causing the calibration drift. By changing the material of the calibration screw, the issue was resolved, stabilizing the calibration and improving the product yield.
This case study highlights Doven Design’s ability to thoroughly analyze and troubleshoot complex issues, leading to practical and effective solutions that enhance product performance and reliability.
Precision Assemblies and Tolerance Stack Management
Case Study:
A client experienced quality issues with a product due to a magnetic switch changing state unexpectedly. The problem arose because the overall design allowed the magnet to move relative to the switch, encountering multiple open/close regions in its path. Supplier quality inconsistencies and the cost vs. precision trade-off led to tolerance stacking that exceeded the normal operating range, causing the switch to change state erroneously.
Reducing component tolerances was deemed too expensive, and a complete design overhaul was not feasible due to the need for recertification with regulatory bodies. To address this, an automated assembly process was developed that accounted for the variance of key components within the switch. This process involved moving the switch reed relative to the magnet until the switch reed changed state. This precisely locates their relative positions accounting for variance in the component magnetic field, ensuring the switch changes state only when intended.
By transitioning from a manual hand assembly to a semi-automated fixture, the client not only resolved the tolerance stacking issue but also increased cycle times and process yields. The video to the side demonstrates a prototype of this automated process, showcasing how the switch's relative positions are calibrated to ensure functionality.
This solution highlights Doven Designs ability to innovate and optimize assembly processes, ensuring precision and reliability while balancing cost and quality considerations.
Industrial Controls
Doven Design has specific experience in designing, improving, and maintaining the manufacturing and quality of electro-mechanical industrial controls. This specific experience has given a broad understanding of various manufacturing processes and an appreciation for the precision and detail required even in seemingly simple components like mechanical on/off thermostats.
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Regulatory Compliance: Skilled in designing and managing parts that adhere to strict regulatory requirements such as UL, CSA, and RoHS, ensuring compliance for large-volume production.
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Cost, Tolerance, and Quality Balance: Adept at finding the optimal balance between cost, tolerances, and quality, crucial for delivering reliable and cost-effective products.
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Supplier and Manufacturer Management: Experienced in working with and managing overseas suppliers and contract manufacturers, ensuring consistent quality and effectively communicating engineering change notifications.
This experience has equipped Doven Design with the skills to oversee the entire lifecycle of products, from initial design through to mass production, while maintaining stringent quality and regulatory standards.
Production Part Design
Designing parts and assemblies for mass production introduces additional layers of complexity compared to prototyping. Each manufacturing process and material must be carefully considered, ensuring that parts are not only manufacturable but also optimized for efficiency and cost-effectiveness. While modern 5-axis CNC machines can produce intricate parts, the cost of such components may not be feasible for mass production. Designing an effective part for a product can be simple, but designing an effective part while keeping costs and tight tolerances to a minimum takes experience. Here are some examples of Doven Designs expertise in this area:
Injection Molding and Die Casting
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Design Considerations: Incorporating draft angles, determining parting line locations, and planning for ejector marks and gates. Ensuring wall thickness is appropriate to prevent shrinkage on critical mating surfaces.
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Collaboration: Working closely with tooling engineers to fine-tune the process and adjust part designs for optimal material flow through the mold.
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Examples: Thermostat enclosures (vinyl, fiber-reinforced polymers), automotive panels, precision camshaft (zinc), heatsinks (aluminum).
CNC Machining
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Tool Path Knowledge: Understanding tool paths and the limitations of common tooling. Designing parts that utilize standard tooling sizes to reduce costs and cycle times.
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Examples: Off-road buggy suspension components (6061 and 7075 aluminum, titanium), hundreds of custom fixture components (Mic-6 aluminum, steel for wear concerns), precision multi-stage bolt assemblies for driving small diameter pins into assemblies (steel using Wire EDM).
Metal Stamping (Single Stage and Progressive)
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Design Considerations: Accounting for material thickness and bend properties, understanding internal stresses in bends, and working with tooling engineers to adjust designs for manufacturing success.
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Examples: Diaphragm disks (thin stainless steel, single stage), complex mechanical thermostat frames (plated steel, progressive 6+ stages).
Joining Processes: Welding, Brazing, Soldering, and Adhesives
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Specific Techniques: Plasma and laser welding for thin stainless steel diaphragms, brazing copper and plated/stainless steel in bulb and capillary systems, and IPC-A-610 compliant soldering for electrical assemblies.
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Examples: Diaphragm welding (thin stainless steel), bulb and capillary system brazing (joining copper and plated/stainless steel), IPC-A-610 electrical assembly soldering.
This comprehensive experience allows Doven Design to design parts and assemblies that are not only functional but also optimized for cost-effective production scaled to the desired output rate. Considering appropriate processes, materials, and tolerances ensures high quality and precision while keeping manufacturing processes efficient.