The Goal

How do we take an existing IM part with complex surfacing, analyze its construction and then replicate it enough that you could replace the existing part with the replicated part?

Project Timeline

December 2022

Course

IDES3106

Design Processes

Design analysis, Part model planning, Sketching, Computer aided design, 3D printing

Software

Solidworks, Sketchbook, Keyshot

Section A

Introduction

Part Chosen

ZTE WF721 Router
Upper Clamshell

Rationale

The part chosen to replicate in this project is an upper clamshell of a router made by ZTE. This part is a fitting and intriguing one because of its deceptively simple features, ribs, and surface structure which both appears simple and complex at the same time.

Section B

Methodology

Visual Analysis

The existing part was analyzed visually to determine its construction, features it uses, its possible surfacing method, and mounting points that can inform the replication process.

Reference Dimensions

The part was traced on paper, and then measured from predetermined points, these measurements were then transferred into Solidworks.

Section C

Part Design

Section D

Prototyping

The final submission part was printed on an FDM 3d Printer (Modified Ender 3) using PLA as the polymer of choice due to its forgiving printing environment demands.

The part was printed in various stages of its replication process, as a way to verify form and dimensions to the best of ability, various printed models is shown.

It was noticed that as more details were added, the print quality became more worse, I assume this is due to the dynamics of the part being inherently more optimized for injection molding, and not for 3d printing as parameters such as wall thickness and ribs are either too thin or too thick in relation to each other, or accounting for parameters such as warping of the polymer being used to print.

Section E

Submitted Prototype
Analysis

Comparison with the original part

Compared with the original part, the replicated prototype is mostly there, with some minor dimensional inaccuracies that was either measured wrong, or tolerances from the FDM process, that resulted in some areas not fitting well or lining up, as seen above

Fitment with the bottom clamshell

When fitting the replicated prototype to the lower clamshell, it was observed that some of the mounting bosses were too long, so it had to be trimmed down in order for the part to reasonably fit.

Section E

Project Debrief

Valuable Insights into the process of not just replicating an existing part, but also designing parts with complex surface geometries.

Utilizing the surfacing features extensively on a complex, injection molded part design gave insight into how different it is from solid-modelling, as well as the unique challenges one can face from dealing with surfacing and how it can be better than some solid features I have been using.

Concerning the part

It was made first in a very trial oriented process, with most difficulties resulting from 2 main sources:

  • Turning the part from a surface into a solid body
  • Solidworks sluggish performance when trying
    to resolve extrusions to surface or complex
    surface bodies
Intricacies of Surfacing, being able to pivot strategies to approaching a part

The main surface was first tried to be converted into a solid using offset surfaces, boundary surfaces and filled surfaces, but that failed to resolve due to artifacts in the surface that made it difficult for those actions to work well in tandem.

That approach was then abandoned and another approach was taken in which a combined method of surface extensions, offset surfaces, thicken features and extrude cuts, that ultimately resolved the main body of the part.

Future Steps

I have gained some insight on how to utilize surfacing features more effectively, and will definitely try to implement, where appropriate; practices and nuances learned regarding surfacing from both this project and the whole course into future projects.