Gate 4 (group 8)

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Reassembly Process

The Jigsaw was fairly easy to reassemble due to the fact that the group had existing knowledge of how the parts should fit into each other from the previous gates. The only tool required for reassembly was the Phillips head screwdriver. The reassembly process is explained below.

Step Process Complexity Picture
1 This picture shows the two pieces that make up the plastic casing. All the parts of the Jigsaw are assrmbled and held together by the two casing shells, which is bound by seven fastners. 1
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2 This picture shows the stator ( on the left) and the armature(on the right). The armature fits into the stator and the carbon brushes are also attached to the armature. 2
Group8gate2re2.jpg
3 This picture shows the armature inserted into the stator( Field assembly) 2
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4 This picture shows the field and armature Assemblies with the thrust plate attached. 2
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5 The picture shows the counter weight (mounted onto the thrust plate) attached to the armature and field Assemblies. 2
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6 This picture shows the gear inserted through the counter weight and the thrust plate into the armature assembly. 2
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7 The shaft assembly is inserted to the motor assembly and the entire Assembly is placed into one piece of the casing while lining it up with the grooves in the casing. 3
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8 The plastic gears at the bottom are inserted into the casing. These gears are used as locking gears for the product. 2
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9 The grip is inserted at the top of the Jigsaw. 1
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10 the power cord is connected to the stator and the switch is inserted at the top of the Jigsaw. 2
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11 The blade guard is inserted at the front of the casing 2
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12 The other part of the casing is inserted over the Jigsaw and the base plate is then inserted. 2
Group8gate2re12.jpg
13 This picture shows the final process in reassembly of the Jigsaw. The screws are inserted. 2
Group8gate2re13.jpg

The Black and Decker Jigsaw is product made for small purpose use in home and small office. When our group examined the product initially we found that it did not work when the power supply was on. We tried to understand the problem as to why it was not working but could not figure it out. We guessed that it was due to some failure in the motor, torn wire or maybe some wear and tear from previous dissection. After disassembly we figured that some parts of the product were lost like parts in the trigger, broken spring load brushes and there were burn and tearing in many parts of the internal wiring. We assembled the product and as estimated it did not work when powered on.

• The product did not run both before and after dissection and disassembly. The main cause was the broken spring load brushes that help in the alternating spinning of the motor inside the armature shell. We tried fixing it but it could not be held together with adhesive and the only replacement could be a new brush. Also the burnt internal wires could only be replaced with new wires and attachment. The trigger assembly had missing parts which made power supply to the motor incomplete rendering the product nonfunctional.


• Our group tried to come up with ways to fix the jigsaw but it could only be fixed by replacing parts. As the product is not that expensive and the replacement could end up costing considerably it is suggested that a new product replacement is done. The disassembly process was a learning process where our team did not understand the working of the product and were concerned with examining its internal components. We spent a lot of time studying every step of disassembly. We took pictures and notes of every step and examined the functioning and relative attachment of each component to the entire product. All our group members pitched in the process of disassembly and we figure out what was wrong with the product. The reassembly was and easier process and we already had the knowledge of what fits where and so only a couple of group member were able to put the product back together.


•For the disassembly we used pliers, Phillip’s screwdrivers and other such tools as this stage was complicated, but for the reassembly we only needed a Phillip’s screwdriver to put thing back into place.


•We were able reassembly the entire product back to the original state. Though some minor parts that were broken could not be attached, they were placed inside the outer casing.


•From this process of disassembly and reassembly our group was able to learn a lot about reverse engineering. The knowhow of how to deduce the workings of a product from looking at its components is a very useful skill and the dissection of the Black and Decker Jig saw definitely has given us the experience needed gain this skill.

We would like to make several recommendations to the company about the jigsaw-


•Setting a variable speed trigger for allowing users to choose different speed levels for the blade to function at.

•A blade holder that releases the blade on the push of a button instead of manual blade changing.

•An additional blade holder on the side for easy carrying of various blades.

•Using lesser grease on the internal components that will reduce manufacturing cost as well as help during disassembly.

•Replacing body screws with seal.

•Provide optional accessories for sale like wireless battery pack.

•Additional upgrades and customization options that would enhance performance.