Redesign of a Soldering Iron
An ergonomic study regarding the usability of a hobby grade soldering iron and redesign of it for an enhanced user experience.
Redesign of a hobby grade soldering iron : Ergonomic study
Project duration: 2 weeks
Mentor: Swati Pal
Group project: Sagar Dabherao, Hazique Kola, Ashuj Chawda
Background: Done as a part of our Ergonomics class, the task was to understand the ergonomics of an existing soldering iron, analyse it by conducting various user tests, and then redesign it (if required) based on the results. The product chosen was a hobby grade soldering iron which is most extensively used among enthusiasts who work on electronics, woodcraft, engravings,etc.
Keywords: Ergonomics, User experience, usability testing, hierarchal task flow
Tools used: Solidworks, Blender, Styrene, PLA, 3D priniting
Context
A soldering Iron is a hand tool that is used for soldering applications. A soldering Iron is an important tool used in any workshop, maker's hub, or prototyping establishment. Soldering iron is primarily used to melt the solder wire on a printed circuit board during electronic prototyping and manufacturing.
The soldering iron is used by hobbyists for various applications that includes Thermocol and foam shaping, wood art, plastic reshaping. The hobby-grade soldering iron available in the market has a number of disadvantages for a user who is not familiar with soldering. There are a few alternatives available in the market. However, the most widely available soldering iron has several shortcomings that include the issue of grip, handling, and the anxiety associated with the hot tip of the soldering iron.
We tried to analyze these pain points and tried solving some of these using design methodologies.
Aim
The aim of the project is to design an ergonomic soldering iron improving posture and visibility of the user reducing physical discomfort and eliminating anxiety associated with soldering iron. The use of soldering iron is in general purpose electronic soldering, thermocol/foam shaping, plastic reshaping, and wood art.
Design approach
Field study
Research
Analysis
Final Design
Concepts & Evaluation
Synthesis
FIELD STUDY
Workspace Analysis
The workspace analysis was conducted to identify the range of movement, placement of different tools in the workspace, and user preferences while soldering.
Inferences from the workspace analysis:
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The soldering iron is used with the dominant hand of the applicator.
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The workspace is generally crowded due to the various components involved in soldering
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There is a need for an electrical socket/ extension cord on the side of the soldering iron so that cord does not get in the way of the soldering process
Task Flow
There are various tasks that are performed chronologically and few of them are repeated until the process is complete.
The following are the process flow involved in the soldering application
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Switch ON the soldering Iron.
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Wait until the soldering iron turns hot.
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Touch the iron tip to the soldering wire to check if it is hot.
3.1) If YES, proceed to 4
3.2) If NO, check if Iron is functioning and repeat from 1
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Prepare the workspace for soldering.
4.1) Turn OFF the iron if it takes too long.
4.2) Turn ON the iron again once done and repeat from 1.
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Take the soldering iron and apply its hot tip and the soldering wire onto the application area simultaneously.
5.1) Apply flux onto the application area for cleaner finishes (optional).
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Wait until the soldering wire melts and sticks/deposits onto the application area.
6.1) Task successful.
6.2) Task not successful.
6.2.1) Clean the application surface with tweezers/wire brush and repeat from 5.
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Lift and place the iron on a comfortable surface.
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Turn OFF the iron.
Soldering process - Time motion study
Lift the soldering Iron from the application surface and confirm if the application is complete. ( Duration: 2 seconds )
Maintaining the contact until the desired application is completed. ( Duration: 5 seconds )
Securing contact between the work piece and the soldering iron (Duration: 3 seconds)
Setting up the workspace, ensuring the right body posture and visibility. ( Duration: 3 seconds )
Picking the soldering Iron and gripping the tool. ( Duration: 2 seconds )
Checking if the soldering Iron is hot by securing contact between the soldering iron and solder wire. ( Duration: 3 seconds )
If the application is not complete or unsatisfactory, repeat the process by securing contact between the soldering iron and the workpiece. ( Duration: 10 seconds )
Rest the soldering Iron on a suitable surface or stand. ( Duration: 3 seconds )
Additional Inferences:
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The soldering Iron takes around 1-3 minutes to heat.
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The solder wire is used to confirm if the soldering iron is hot. Soldering iron ready conformation: Use soldering wire to confirm
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Approximate time for application on one point: 15 seconds
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Cycle is repetitive in nature
RESEARCH
Secondary Research
Tool specifications
The following tools specification are for the widely available Soldering Iron which is considered for design intervention in this project.
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The average length is 25 cm from the tip to the base of the soldering iron from where the wire starts.
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The approximate weight is 0.2 kg
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The maximum diameter of the outer component is 2 cm
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The approximate length of the electrical wire is 1.5 m
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The length of the tip is 11 cm.
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The power rating is 25 W.
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The operating voltage: 110 ~ 230 VDC
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Temperature: 200-480 Degree C
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Material of body: Bakelite
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Tip Diameter: 3.55 mm
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The material of tip is High-Quality Nickel-Copper plated Bit
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The price is Approx 150 INR
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Application Area: Since 90% of the users are for electronic soldering, the tip of the soldering iron is the only contact area of application.
Market study
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Stanley 69-031B Soldering iron
Price: Rs 499/-
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60W Adjustable Temperature Soldering Iron - High Quality
Price: Rs 647
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Soldron 936/960/878D/740 Stations
Rs.1349.00
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12W Micro Soldering Iron Station (Used Mainly for SMD Components)
Rs.390.00
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D&V Electro Smart Heavy Duty 60W/230V Soldering Iron any Hobby KIT
Rs 175.00
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Soldron 75W/230V High Quality Soldering Iron
Rs.599.00
Inferences:
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There are a wide variety of products available in the hobby segment of the market. The features of the products are changed with respect to the application.
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Few products offer temperature control with a knob in the station.
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The user issues identified in our research are consistent in the selected market study products.
Based on the secondary research, a few ergonomic factors must be considered for designing a hand tool such as a soldering Iron.
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The weight of the soldering iron should not exceed1 kg.
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The handle diameter should be 5mm to 12 mm.
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The handle length should be 115 mm to 120mm.
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The handle should be covered with a textured grip.
Primary Research
Interviews
Person 1
Name: Baidurjya Deka
Occupation: Engineer at Deloitte
Background: Electronics & Communication Engineering
Interview Insights:
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Uses it for general electronics projects
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Handling problem - reduces precision
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Tip too long - the danger of holding in the front hot region
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Overheating - damages the tip
Person 2
Name: Adith Philip Mathew
Occupation: Engineer at Foley Designs, Bangalore
Background: Mechanical Engineering
Interview Insights:
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Uses 3 finger pencil grip.
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He’s extremely anxious about the hot surface causing accidents.
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Uses Table to rest the soldering iron.
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Uses it on thermocol, wood, paper, or any surface.
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Finds it difficult to use solder wire, flux and soldering iron at the same time.
Person 3
Name: Mohammed Rayaan
Occupation: Animation Design, IDC, IIT Bombay
Background: Electronics & communication engineering
Interview Insights:
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Few hours while the project is going on.
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Finds the longer soldering iron difficult to use, searched for soldering iron with a smaller tip
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Uses a wooden block/table to rest the iron.
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Finds it difficult to solder wire. No control.
Person 4
Name: Dhanush GT
Occupation: Product Manager, Gordian Technologies, Bangalore
Background: Mechanical engineering
Interview Insights:
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He uses it often, half an hour a day, 3 days a week.
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Uses makeshift stands to rest the soldering iron.
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He's worried about people walking in and hurting themselves on the hot soldering iron.
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While trying to get good visibility, the smoke gets into the eye and nose causing irritation.
Questionnaire
The following questions were targeted towards hobbyists, creators, inventors and maker lab professionals. The focus of this questionnaire was to understand the context of application and identify the user issues qualitatively.
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How often do you use the soldering iron?
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On the scale of 1 - 5, how much is your vision blocked while soldering? How difficult do you find to see where you are exactly soldering?
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What all do you use soldering iron for?
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Are you anxious because of the hot area while using soldering iron?
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Where do you rest your soldering iron while working?
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Where do you keep your soldering iron while not in use?
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How do you hold your soldering iron while working?
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Do you feel frustrated/annoyed because of soldering iron experience?
ANALYSIS
Analysis of existing soldering Iron
Analysis of existing soldering iron was performed based on conclusions made from the primary user research.
The following were the points of consideration while evaluating the existing soldering Iron
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User grip
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User precision
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Comfort while keeping the soldering iron at rest
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Visibility
Conclusions based on the analysis conducted:
The users were asked to grade the soldering iron from 1-5 based on their experience. The following results were obtained by taking the average of the scores by the individual user.
Parameter
Ease of grip
Precision
Comfortable length of tip
Hot tip anxiety
Comfort in resting on table
Score
2
2.6
2
3.4
1
Relevance
Posture Analysis
Analysis of existing soldering iron was performed based on conclusions made from the primary user research.
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Due to difficulty in precision grip, the user tends to bend towards the area of application in order to focus.
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The user tends to lean towards the area of application while soldering and leans back after the application is complete.
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This repeated motion is the cause of discomfort with respect to posture.
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Posture when the user begins the application
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Posture while the user is checking if the soldering application is successful
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Posture while the user is soldering
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Posture while the user has completed the soldering application
Posture analysis conclusions:
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The user leans towards the workpiece to get a better view of the process.
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While the soldering process is complete and while resting, the user comes back to natural resting position.
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Since soldering is a repeated process, the user undergoes the change from natural to awkward posture multiple times during the whole process, which is a cause for stress to the user.
SYNTHESIS
User needs
All the research insights were molded to come up with the most prominent user needs. The four most important needs were identified as mentioned below.
Precision grip: Most users use Pencil type precision grip to use the device but unable to use the device at one point precisely
Reduced Hot tip anxiety: The users are constantly worried about the hot tip causing accidents apart from lack of temperature feedback from the device.
Table for resting: Most users do not employ special stands to keep soldering gun while not in use.
Improved Visibility: Bulky nature of the iron partially compromises the visibility of the user causing increased effort and awkward posture.
Design Brief
To redesign an ergonomic soldering iron to improve posture and visibility of the user reducing physical discomfort and eliminating anxiety associated with soldering iron.
CONCEPTS & EVALUATION
Concepts
A number of concepts were developed to fulfill the design brief. The following are the concepts that were selected
Concept 1
Features:
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Pencil type grip
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Flat side to rest on the table
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Slider for the soldering gun to retract
Pros:
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No hot tip anxiety since the soldering gun retracts into the form.
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Good Precision Grip
Cons:
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Manufacturing is a challenge
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Increased cost
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Maintenance is difficult
Concept 2
Features:
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Pencil type grip
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Slider Cap to eliminate hot tip anxiety
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Pointed Soldering tip
Pros:
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No hot tip anxiety since the slider cap covers the soldering tip
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Good Precision Grip
Cons:
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Manufacturing is a challenge
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Increased cost
Concept 3
Features:
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Anti-roll body
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Modular design
Pros
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Very comfortable to handle
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No hot tip anxiety
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No need of an external stand
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No damage to the table
Cons
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Bulky
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Extra material
Mockups
The concepts were analyzed for relevance to the design brief and mockups were developed and tested.
Mock-up 1
Mock-up 2
Mock-up 3
Mock-up 4
Mockup Evaluation
The models were evaluated by the users and average score for parameters are shown below
Different parameters were evaluated for the mockups made.
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The following table shows the models in which the features have a prominent effect on the test parameters.
These mockups were analyzed and significant features were incorporated for final concept development.
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FINAL DESIGN
Final Concept
The final concept was developed with the help of user studies, interviews, and feedback from the previous tests that were conducted.
The final prototype has an ergonomic triangular form for the handle and grip. The triangular handle makes it easy for the soldering Iron to rest on the table. The magnetic slider opens and closes to ensure that the tip is covered. This reduces the hot tip anxiety as the tip is covered. There is a light indicator that is ON when the soldering Iron is ready to use and OFF when the temperature of soldering Iron is below the required temperature.
Testing and validation of the final concept variations
The final concept was tested with three different handle sizes, and three different tip lengths, with a cap.
Handle sizes that were tested ( Variation: outer diameter ) :
12mm - Model 2.1
14mm - Model 2.2
16mm - Model 2.3
Tip sizes that were tested ( Variation: length ):
25mm - small
50mm - medium
75mm - large
User testing for existing soldering Iron
User testing for different variations of developed concepts
The table below shows the average value of user testing scores with respect to the following parameters and were graded between 1-5
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Grip
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Precision
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Comfortable length of the tip
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Hot tip anxiety
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Comfort in resting on the table
Parameter
Ease of Grip in existing model
Ease of Grip in Model 2.1 - 12mm
Ease of Grip in Model 2.2 - Medium dia
Ease of Grip in Model 2.3 - Big dia
Precision of existing model
Precision of Model 2.1 - Small dia
Precision of Model 2.2 - Medium dia
Precision of Model 2.3 - Large dia
Comfortable length of tip for Precision
Anxiety - Existing Model
Anxiety - Final Model
Comfort in Resting on table - Existing Model
Comfort in Resting on table - Final concept
Score
2
3.4
3.8
2.8
2.6
3.8
4
3.4
Medium
4.2
1.2
1.4
4.4
The medium diameter of 14 mm and the length size of 50mm was chosen for the final prototype.
Conclusions:
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The comfort score in Resting on the table was increased from 1.4 to 4.4 in the final concept
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The anxiety score associated with hot tip reduced from 4.4 to 1.4 in the final concept
Final Prototype
Exploded view
Prototype
Testing for rest on table
Testing for grip
Testing for visibility
Testing with cap
Testing Final prototype with existing model for visibility
Testing Final prototype with existing model for precision
Testing prototype with existing model for comfort resting on table
Final prototype with attached magnifying glass
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