DESIGN OVERVIEW

 

Stock support bars are placed along each corner of the triangular prism in the z-direction. Modified stock carriages, whose movement is controlled by stepper motors couple with timing belts and GT2 systems, slide up and down on these support bars. The position of the nozzle is controlled by a parallel manipulator mechanism that characterizes delta style printers. The key advantages of this mechanism is its spatial ergonomics and ability to affordably increase print accuracy.

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Context

 

THE OPPORTUNITY

 

PRIMARY STAKEHOLDER

3D printing is the future of design. 3D printing is accelerating the ability of professionals across a multitude of industries fro healthcare to fashion to manufacture prototypes and is bringing higher fidelity tools to hobbyists alike. Design of 3D printers for entry-­level professionals running print farms is particularly accessible and high demand.

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ENGINEERING SPECIFICATIONS OVERVIEW

With the primary stakeholder in mind, the design was scoped such that the print mechanism would be fused deposition modelling (FDM) system. This is due to its low initial costs and post-­print processing costs. FDM is a method whereby a filament of plastic is fed through a nozzle that melts the filament and extrudes it onto a print table. The extrusion path forms a microscopic layer of the overall desired print output. In our engineering specification, we prioritized ease of use, high print quality, low to medium cost, and high efficiency in a print farm configuration (efficiency consisted of: a medium to ­low footprint and minimizing time and effort to prepare for, set up, and remove each print job). 

Some design spec highlights:
 

Dimensions and Manufacturing information

- Maximum overall size (footprint): H = 50 cm, B = 35 cm, W = 35 cm

 

Cost

- Maximum unit cost: $2,000

- Maximum cost per print volume: less than $2 per cm³

 

Operation

- Print farm compatible: at least 20 printers should be able to be operated at a time by one user

- Must include data resurrection mechanism

- Calibration: must be automated

- Print removal: should minimize time and effort for print removal

- Maintenance Process: must have standard fasteners that require only standard tools

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Printing Quality and Specifications

- Extrusion speed: must be electrically controlled and with a range within 20 to 600 mm/s

- Table area: must be greater than 200 cm²

- Resolution: must be at least 300 microns

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FINAL DESIGN KEY FEATURES

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Spatial Ergonomics: 

• The design enables a configuration of 6 single unit printers in a hexagonal or linear pattern formation

• In any formation, the print is accessible from all sides of the printer

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Easy Assembly: the design has a removable base and top plate

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Easy Manufacture: the design utilizes stock parts found on McMaster Carr where possible

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Chemically Treated Print Table: a layer of liquid alcohol applied to the base of the print smoothly removes the print (rather than applying pressure that may damage the print)

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Low Cost: the raw materials & stock material cost before manufacture is ~550 CAD and all parts of the design aside from casing and calibration system assembly are assembled by the user

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Process

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DESIGN STAGES

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From engineering specifications developed through primary and secondary market and technical research, two candidates were created. Each candidate was evaluated against the engineering specifications and then were compared to each other. Iterations on these designs evolved into our final design -- a hybrid of the two primary designs.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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DRAWINGS

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RENDERINGS

 

 

 

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KEY DESIGN DECISIONS

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• Using a vertically, belt driven parallel manipulator -> fewer custom parts

• Machining stock parts for assembly to the correct dimensions -> more ergonomic design

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DESIGN WEAKNESSES

• The use of belts introduced the need for more maintenance, since belts are wearing parts and require frequent servicing.

  • MITIGATION: Reducing the cost while conserving space was more economic and thus acts as a buffer for the drawbacks of increased wear.

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See full design report and Appendices

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My Role

 

TECHNICAL WORK

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I aim to be an essential member fro end-to-end. 

I initiated the user interview and was the primary contact for communications. 

I contributed sketches to iterative design and facilitated design team meetings in terms of brainstorming and evaluation techniques.

When it came time for realizing our design, the:

1. filament holder design,

2. the support bars,

3. the sliders,

4. the belt tension spring,

5. the extrude sourcing and specification,

6. the pulley specification and modification, and

7. the top and bottom housing components (including custom brackets) 

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were all components that I designed/modified and CAD'd/assembled myself.

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MY TEAM

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This design contains a lot of blood, sweat and tears. But, it was also a limited course exercise, during which every member had the burden of full course loads and extracurriculars. Understanding my team's context as well as my teammates is a key part of building effective teams. In order to optimize our skills, motivations and schedules, I facilitated setting team expectations our first meeting -- this included stretch goals, dreams and collectively identifying grunt work, not just 'etiquette' and communication channels. With that value and investment in each other, our team aimed to do everything together, even if it was counter productive sometimes, in order for all of us to learn the skills necessary at each stage. This was an awesome learning experience!