ERGONOMIC SANDER
Designing for the 5th percentile female, to the 95th percentile male, and beyond.
PROBLEM ANALYSIS
MALE vs FEMALE DATA AND BARRIERS
4 key factors impacting women’s comfort with power tools include physical differences, exposure levels, and representation in product development. Addressing these enhances usability for all users.
CURRENT TOOL ANALYSIS
I analyzed various pneumatic tools, decided to focus my redesign on the palm sander as it relies heavily on grip strength and hand size, two major discrepancies between female and male anthropometrics.
ERGONOMIC RESEARCH
KEY CONSIDERATIONS:
Tools should allow wrist to stay straight
Weight distribution is important
Use power grip whenever possible
Max 1.4kg for single handed tool
Vibration absorption
Center of gravity close to handle
Rounded, cylindrical, or oval shaped handles
Handle must be at least as long as palm
Handles should be non-slip
ERGONOMIC ANALYSIS OF EXISTING MODELS
CONCLUSION: incorporate a power grip more central to the centre of mass, combining the pros of each model
INITIAL IDEATION
FIRST TEST
Model confirmed theory of adding the handle on top was possible and beneficial.
Centre of mass too far away from handle, similar to dual-action sander
Need to make the internals smaller
PRODUCT TEARDOWN
The product teardown was critical in helping me understand the internals and their functionality, crucial later in the design process when I had to redesign the internals to suit the ergonomic needs.
MOTOR REDESIGN
SKETCH OVERLAY DETERMINING NECESSARY MOTOR HEIGHT
ASSESSMENT AND CALCULATIONS FOR PROPOSED CHANGES
Options for shortening motor:
Complete new, higher density material – easiest/costly
Steel, but reconfigured into new weight distribution
Add small pieces of high density material to steel
WORKS-LIKE MODEL & TESTING PLAN
6 different surfaces set up to mimic different sanding projects
A weighted proof of concept model simulated a realistic use cycle
KEY INSIGHTS
Power grip handle not suitable for all postures, need to reincorporate palm grip.
Two handed postures were common
Need to increase affordance between handle and base
Handle profile needs to reduce rotation
HANDLE DEVELOPMENT
Based on results of previous testing, I developed new handle profiles to be tested.
SWITCH/THROTTLE
Modified the switch to make using the sander easier, being able to adjust the power with a designated switch instead of a hand lever.
I made the throttle larger in diameter so it could act as both the on/off and power adjuster.
AIR INTAKE/OUTTAKE
With the shortened base, I reconfigured the intake/outtake ports so they wouldnt interfere with hand placement during use.
UPDATED PROOF OF CONCEPT
Palm grip for curved surfaces
Power grip for vertical surfaces
Updated model includes:
new handle profile, rounded triangle
reincorporated palm grip, with weights at center
better representation of air intake and outtake ports
FINAL FORM DEVELOPMENT
PALM GRIP
Iterating and testing new palm grip profiles
Taking feed back and sculpted a softer, smaller shape
FINETUNING SPACING
GRIP DETAILS
Sketch overlays and Illustrator made it easy to swap out options and colours. Grip needed to fully surround handle to accommodate the variety of possible hand postures.
FINAL DESIGN
WHAT I LEARNED
The value of a product teardown, the teardown really informed the constraints I was working within and helped guide what structural changes were possible for the sander housing.
To not get ahead of myself before testing, I got attached to the idea that the new power-grip handle was a cure-all but the testing phase immediately disproved my original hypothesis and had me re-introducing the palm grip.
Manufacturing, I learned a lot about the limitations of manufacturing and got a lot of good insight through lengthy discussions with my professor in the development phase.