Difference between revisions of "Group 29 - Black and Decker Jig Saw"

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('''Post-Assembly''')
 
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- Our Black and Decker Jig Saw does not work now due to lost parts within the trigger assembly.
 
- Our Black and Decker Jig Saw does not work now due to lost parts within the trigger assembly.
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- This linear energy is used to cut materials because the blade holder is going up and down at a fast rate
 
- This linear energy is used to cut materials because the blade holder is going up and down at a fast rate
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- Testing of the variable speed motor could be done to see how much power is needed for certain speeds and also on how much heat is dissipated when the motor is in use so overheating can be avoided.  For these tests you would need precise models.
 
- Testing of the variable speed motor could be done to see how much power is needed for certain speeds and also on how much heat is dissipated when the motor is in use so overheating can be avoided.  For these tests you would need precise models.
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- We were able to reassemble the entire project except for the trigger assembly that we took apart.  It was very hard to assemble this part because it was all spring loaded and it was tough to try and force all of the parts back together. While trying to reassemble the trigger we lost some parts thus making the trigger not function properly.
 
- We were able to reassemble the entire project except for the trigger assembly that we took apart.  It was very hard to assemble this part because it was all spring loaded and it was tough to try and force all of the parts back together. While trying to reassemble the trigger we lost some parts thus making the trigger not function properly.
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- More Power: Although we were unable to actually test the tool out, it would seem that the jigsaw would have a difficult time with larger tasks.  If the engine were to be made larger it would give the jigsaw the power needed to do big jobs as well as make small tasks easier.
 
- More Power: Although we were unable to actually test the tool out, it would seem that the jigsaw would have a difficult time with larger tasks.  If the engine were to be made larger it would give the jigsaw the power needed to do big jobs as well as make small tasks easier.
 +
  
  
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- Make the jigsaw more difficult to take apart, so that consumers cannot get inside and void the warranty
 
- Make the jigsaw more difficult to take apart, so that consumers cannot get inside and void the warranty
 +
  
  

Latest revision as of 15:59, 10 December 2007

Black and Decker Jig Saw


Contents

Executive Summary

Power drills and saws are common tools necessary in any kind of construction. My group fully disassembled a Black & Decker Jigsaw and examined all the different parts it was made up of. We found out what kind of materials were used and how those materials were manufactured. Prior to the disassembly, we thought of it's usage, took an educated guess on how many parts the jigsaw consisted of, and assumed its features and how they work.

Introduction

The Black and Decker Jigsaw is a power tool used to cut sharp turns, with the ability to switch blades very simply. We dissected the jigsaw, named each part and analyzed the saw completely.

Our group equally worked on the project and consisted of the following members:

Mike Fama

Craig Castiglione

John Kresconko

Rex Chan

Ryan Spies

Pre-Disassembly

Purpose of the Jigsaw

The purpose of the Jigsaw is to cut different intricate bends into a piece of thin wood. The Jigsaw has the capability to cut sharp curves and turn at a small radius, where most saws only allow you to cut in straight lines.

Operation

The Jigsaw receives AC power from a wall outlet from which it is supplied to the motor. The motor then creates rotational mechanical energy which is then converted through a series of gears to produce linear motion/energy. This energy allows the blade to move up and down rapidly when the trigger is activated.

Amount of Components

Estimated number of components:

  1. Screws
  2. Casing
  3. Cutting Deck
  4. Blade Holder
  5. Gel Pad
  6. Trigger
  7. Wiring
  8. Motor
  9. Gears

Types of Materials

Estimated types of Materials:

  1. Steel
  2. Plastic
  3. Rubber
  4. Copper
  5. Gel

Disassembly

Disassembly Process Table

Step Number Process Tool Level of Difficulty
1 Remove 7 Phillips-head screws Phillips-head Screwdriver Easy, 1 Screw Quite Difficult
2 Removed Rip Fence Bolt to Saw Blade Locking Lever By Hand Easy
3 Removed Removed Dust Blower Angle off of Dust Blower By Hand Easy
4 Removed Dust Blower and Rip Fence off of Casing By Hand Easy
5 Removed Rip Fence off of Casing By Hand Easy
6 Removed Plastic Blade Guard off of Casing By Hand Easy
7 Removed Casing off of Casing Philips-head Screwdriver Moderately Easy
8 Removed Gel Max Comfort Grip off of Casing By Hand Easy
9 Removed Shoe Plate Locking Gear off of Casing By Hand Easy
10 Removed Shoe Plate Locking Knob off of Casing By Hand Easy
11 Removed Trigger Switch off of Casing By Hand Easy
12 Removed Lock on Button off of Trigger Switch By Hand Easy
13 Removed Lock Spring off of Lock on Button Flat-head Screwdriver Easy
14 Removed Plastic Lock Washers off of Lock on Button Flat Head Screwdriver Moderately Difficult
15 Removed Switch Breaker off of Trigger Switch By Hand Easy
16 Removed 2 Cord Clamp Screws off of Cord Clamp off of Casing Phillips-head Screwdriver Easy
17 Removed Red Motor Connecting Wire off of Spring Loaded Graphite By Hand Easy
18 Removed Black Motor Connecting Wire from Spring Loaded Graphite By Hand Easy
19 Disassembled Spring Loaded Graphite Internals By Hand Easy
20 Removed Motor Screw From Casing Philips-head Screwdriver Easy
21 Removed Red Motor Connecting Wire From Armature By Hand Easy
22 Removed Black Motor Connecting Wire from Armature By Hand Easy
23 Removed Metal Gear From 1/4in. Plate By Hand Easy
24 Removed 1/4in. Metal Plate from Armature Shaft With Rotar By Hand Easy
25 Removed Small Metal Plate off of Armature Shaft With Rotar By Hand Easy
26 Removed Linear Oscillator from Metal Gear By Hand Easy
27 Removed Washer off of Gear from Metal Gear By Hand Easy
28 Removed Cylindrical Slider from Linear Oscillator By Hand Easy
29 Removed Blade Changing Piece from Blade Changing Component By Hand Difficult
30 Removed Blade Changing Spring from Blade Changing Component By Hand Easy
31 Removed Allen Wrench Screw from Blade Changing Component 3/32 Allen Wrench Easy
32 Removed Blade Changing Component from Linear Oscillator By Hand Easy
33 Removed Felt Piece from Linear Oscillator By Hand Easy
34 Removed Cylindrical Slider 2 from Linear Oscillator By Hand Easy

Parts

Part Table

Part # Part Name Quantity Material and Reason for Choice of Material Function Reason for Shape Manufacturing Process Image CAD Crawings
1 Casing Screws 7 Steel which is needed for a sturdy screw Holds casing and parts inside casing together A good design to pull two pieces together Machined
Casing screws.jpg
2 Saw Blade Locking Lever 1 Steel because it needs to withstand twisting and direct force. A bar to keep the rip fence sturdy To lock in on many points along the bottom Machined
Saw blade locking lever.jpg
3 Rip Fence Bolt 1 Steel because bolts need to be strong enough to endure twisting and regular force To hold the rip fence onto the casing So it can pull two objects together Molded then Machined
Rip fence bolt.jpg
4 Dust Blower Angle 1 ABS Plastic because it does not take a lot of wear and tear. Also it is cheap and easy to make To be a pathway for sawdust and air when a vacuum is attached To turn so the angle can pick up sawdust directly off of what is being cut Injection Molded
Dust blower angle.jpg
5 Dust Blower 1 ABS Plastic because it does not take a lot of wear and tear. Also it is cheap and easy to make To be an opening for the pathway which the dust will flow through To be an opening so it can pick up dust and be pressure fit to the rip fence Injection Molded
Dust blower.jpg
6 Rip Fence 1 Steel because the bottom will be rubbed and hit as it is used quite often To provide a guide and a base with which to push down on and move the blade It is flat so it is easy to push and guide the blade along it's path Injection Molded, Machined
Rip fence.jpg
7 Right Side Casing 1 ABS Plastic because it is durable and when it is thick it can deal with a lot of abuse and punishment To hold all the parts together along with screws To hold all parts in one area and keep them from moving in ways they aren't supposed to Injection Molded
Casing 1.jpg
8 Left Side Casing 1 ABS Plastic because it is durable and when it is thick it can deal with a lot of abuse and punishment To hold all the parts together along with screws To hold all parts in one area and keep them from moving in ways they aren't supposed to Injection Molded
Casing 2.jpg
9 Plastic Blade Guard 1 Plastic because it is a part you look through to see the blade and to protect a persons hand from the blade To guard the front of the blade so nothing hits the blade that is not supposed to to cover an area to make it inaccessible to hands and fingers Injection Molded
Plastic blade guard.jpg
10 Gel-max Comfort Grip 1 Gel because it gives and helps absorb the vibrations of the jigsaw To comfort the hands of user To cover and area where the users hands would be Manufactured
Gel-max comfort grip.jpg
11 Shoe Plate Locking Gear 1 Plastic because it is cheap and easy to make and the part does not take much punishment The person spins it to lock the rip fence in place at a certain angle It is a gear with teeth to turn another gear locking the rip fence Injection Molded
Shoe plate locking gear.jpg
12 Shoe Plate Locking Knob 1 Plastic because it is cheap and easy to make and the part does not take much punishment The person turns the knob with their fingers to lock the rip fence in place It is a gear and knob with teeth to turn another gear to lock the rip fence in place Injection Molded
Shoe plate locking knob.jpg
13 Trigger Switch Component 1 Plastic, Copper, Steel, Aluminum because all these are need to get current to flow through it into the motor To control rate of flow of current to the motor It is made so there is a constant flow and path of a certain amount of current to the motor Manufactured
Trigger switch.jpg
14 Lock on Button 1 Plastic because it is cheap and easy to make and the part does not take much punishment It locks the trigger so that it cannot turn the engine on It has two sides so it can be pressed and a small dash in the middle so it can block the trigger Injection Molded
Lock on button.jpg
15 Lock Spring 1 Steel to make a durable and strong spring It helps make moving the locking trigger easier It is made in the spring shape to force an object in one direction Manufactured
Lock on spring.jpg
16 Plastic Lock Washers 2 Plastic because they do not get much force on them and it is cheap to make It is to be put on either side of the spring and holding it there It is made to hold the spring so it will not slip and be wide enough so all the force will be transfered Injection Molded
Lock on plastic washers.jpg
17 Switch Breaker 1 Aluminum because it is conductive to metal and will melt breaking the circuit if to much current flows through A circuit breaker that causes the jigsaw to stop working of too much current starts to flow through it It is cheap and melts at relatively low temperatures and can handle current going through it Machined
Switch breaker.jpg
18 Cord Clamp Screws 2 Steel because they need to be durable and withstand the torque and shear force To push down on the cord clamp to hold the cord in the casing It was made to pull the cord clamp against the cord Machined
Cord clamp screws.jpg
19 Cord Clamp 1 Steel because it needs to be strong and is pushed against things The screws push on it and then it in turn pushes on the cord to keep it in the casing it was made that way to push evenly on the cord and near flat to save on manufacturing costs Injection Molded, Machined
Cord clamp.jpg
20 Red Motor-connecting Wire 1 Rubber and Copper which are great insulating and conducting properties It conducts electricity from the trigger to the motor It is made to conduct electricity as efficiently as possible and the rubber to insulate it Manufactured
Red wire.jpg
21 Black Motor-connecting Wire 1 Rubber and Copper which are great insulating and conducting properties It conducts electricity from the trigger to the motor It is made to conduct electricity as efficiently as possible and the rubber to insulate it Manufactured
Black wire.jpg
22 Spring Loaded Brushes 2 Plastic, Copper, Graphite because they are what is used for a AC to DC motor It changes electricity from AC to DC It is made because those materials are needed for the translation of AC to DC Manufactured
Spring loaded brushes.jpg
23 Motor Screw 1 Steel because of high stress and torque put on it It helps hold the motor to the casing It pulls the motor onto the casing and holds it there Machined
Motor screw.jpg
24 Armature 1 Steel, Copper, ABS Plastic to be durable and cheap This part is the inside of the motor and a fan to keep the sawdust away They are all made to do each job as efficiently as possible Machined
Armature 2.jpg
25 Metal Gear 1 Steel for it's durability It is turned by the motor and spins It is a gear and helps turn other parts of the jigsaw Machined
Metal gear.jpg
Part 27.jpg
26 1/4 Inch Metal Plate 1 Steel for it's durability Helps keep everything in place It was made thick and strong due the vibrations and forces that act upon it Machined
Metal plate.jpg
27 Small Metal Plate 1 Steel for durability To help hold everything in place Made thin because it vibrates and is used to protect the large plate from abrasion with a large amount of grease between each of them Machined
Small metal plate.jpg
28 Armature Shaft with Rotor 1 Steel, Copper, ABS Plastic, Tape Part of the motor that alternates to turn the inside causing the rotation Made to turn electrical energy into mechanical energy Machined
Armature.jpg
29 Linear Oscillator 1 Steel for durability Oscilates up and down moving the blade In this form it is highly durable and can move easily Machined
Linear.jpg
Part31.jpg
30 Washer off of Gear 1 Steel for durability Moves inside the hole on the linear oscillator and pushes on it in a vertical direction It is formed this way to fit in the linear oscillators hole and have the least amount of friction possible Machined
Washer off of gear.jpg
Part32.jpg
31 Cylindrical Slider 2 Steel for durability This is to align the linear oscillator to keep it in line and moving up and down It is made to be simple and cheap but still strong enough to deal with the friction Machined
Cylindrical slider.jpg
Part33.jpg
32 Blade Changing Piece 1 Plastic for durability and to keep cost down It pulls up the springs and the blade holder to allow the old blade to fall out and put the new blade in It just needs to endure a momentary pull of the finger so it is not thick or strong Injection Molded
Blade changing piece.jpg
33 Blade Changing Component 1 Steel for durability It holds the springs and blade changing piece and pushes down on the blade to keep it in place with help of the springs It is built for the least use of materials and just enough to do what it needs to do. Cast
Blade changing component.jpg
34 Blade Changing Spring 2 Steel for durability It pulls the blade changing component onto the blade holding it in place It is built to have a large amount of force behind it to endure the fast rate at which the blade is moved Manufactured
Blade changing spring.jpg
35 Alan Wrench Screw 2 Steel for durability It holds all of the blade changing components in place It is built to pull to objects together Machined
Alan wrench screw.jpg
36 Felt Piece 1 Felt for shock absorption This to absorb any impact the motor may hit linear oscillator wiht It is minimally built to cover the area's that may be hit Manufactured
Felt piece.jpg
Part39.jpg

Product Improvements

Battery Operated

- Cord can be a safety issue

- Hampers mobility

- Limits use to within a certain displacement of an outlet


Insulate Plastic

- Saw runs loud

- Insulating plastic will reduce noise


Laser Guide

- Help provide more accurate cutting


Increase Amount of Gel Max Comfort Grip

- With long use more gel will maintain comfort

Assembly

Assembly Process Table

Step Number Process Tool Level of Difficulty
1 Attach Cylindrical Slider 2 to Linear Oscillator By Hand Easy
2 Attached Felt Piece to Linear Oscillator By Hand Easy
3 Attached Blade Changing Component to Linear Oscillator By Hand Easy
4 Attached 2 Allen Wrench Screws to Blade Changing Component 3/32 Allen Wrench Easy
5 Attached Blade Changing Spring to Blade Changing Compenent By Hand Easy
6 Attached Blade Changing Piece to Blade Changing Component By Hand Easy
7 Attached Cylindrical Slider to Linear Oscillator By Hand Easy
8 Attached Washer of Gear to Metal Gear By Hand Easy
9 Attached Linear Oscillator to Metal Gear By Hand Easy
10 Attached Small Metal Plate to Armature Shaft with Rotar By Hand Easy
11 Attached 1/4 in Metal Plate to Armature Shaft with Rotar By Hand Easy
12 Attached Metal Gear to 1/4 in Plate By Hand Easy
13 Attached Black Motor Connecting Wire to Armature By Hand Easy
14 Attached Red Motor Connecting Wire to Armature By Hand Easy
15 Attached Motor Screw to Casing Phillips-head Screwdriver Easy
16 Attached Spring Loaded Graphite Internals By Hand Easy
17 Attached Black Motor Connecting Wire to Spring Loaded Graphite By Hand Easy
18 Attached Red Motor Connecting Wire to Spring Loaded Graphite By Hand Easy
19 Attached 2 Cord Clamp Screws through the Cord Clamp to the Casing Phillips-head Screwdriver Easy
20 Attached Switch Breaker to the Trigger Switch By Hand Easy
21 Attached Plastic Lock Washers to the Lock on Button Flat-head Screwdriver Moderately Difficult
22 Attached Lock Spring to the Lock on Button Flat-head Screwdriver Easy
23 Attached Lock on Button to the Trgger Switch By Hand Easy
24 Attached Trigger Switch to the Casing By Hand Easy
25 Attached Shoe Plate Locking Knob to the Casing By Hand Easy
26 Attached Shoe Plate Locking Gear to Casing By Hand Easy
27 Attached Gel Max Comfort Grip to Casing By Hand Easy
28 Attached Casing to Casing By Hand Easy
29 Attached Plastic Blade Guard to Casing By Hand Difficult
30 Removed Rip Fence to Casing By Hand Easy
31 Attached Dust Blower and Rip Fence to Casing By Hand Easy
32 Attached Dust Blower Angle to Dust Blower By Hand Easy
33 Attached Rip Fence Bolt to Saw Blade Locking Lever By Hand Easy
34 Attached 7 Phillips-head Screws Phillips-head Screwdriver Easy

Post-Assembly

Assembly Review

- Assembly was just as easy as the disassembly with the exception of the trigger component. The trigger's spring loaded technology made it difficult to assemble, and a few parts were lost.


Functionality

- Our Black and Decker Jig Saw does not work now due to lost parts within the trigger assembly.


How it Works

- The electrical cord is plugged into a standard AC outlet

- The outlet provides AC power which is brought in through the electrical cord to the trigger

- When the trigger is pressed the power is converted to DC power which goes to the motor

- The speed at which the motor rotates is dependent on how much the trigger is depressed

- The motor then converts this DC power to rotational mechanical energy in the output shaft

- The output shaft of the motor connects to a gear that converts the rotational mechanical energy to linear energy on the blade holder

- This linear energy is used to cut materials because the blade holder is going up and down at a fast rate


Analysis Tests

- Impact and shock testing could be done on the whole product and we could use estimates for these tests.

- Test individual parts for durability, wear, and tear; estimates could be used for this type of testing.

- Testing of the variable speed motor could be done to see how much power is needed for certain speeds and also on how much heat is dissipated when the motor is in use so overheating can be avoided. For these tests you would need precise models.


Disassembly/Assembly Process

- The disassembly process was the exact opposite of the assembly process which was very convenient, this is because most of the parts went together rather simply.

- We used the same exact tools for each step.

- We were able to reassemble the entire project except for the trigger assembly that we took apart. It was very hard to assemble this part because it was all spring loaded and it was tough to try and force all of the parts back together. While trying to reassemble the trigger we lost some parts thus making the trigger not function properly.


Design Changes

Throughout the disassembly and reassembly our group noticed that the jigsaw was remarkably well designed. The saw works perfectly well with its current design. Some ideas we did come up with for slight improvements were as follows.

- Remove Cord: We found that the cord was a safety hazard. people could trip on it, or end up cutting through it.

- Less Internal Grease: The internal components of the jigsaw were coated in an excessive amount of grease. It is unnecessary and messy.

- More Power: Although we were unable to actually test the tool out, it would seem that the jigsaw would have a difficult time with larger tasks. If the engine were to be made larger it would give the jigsaw the power needed to do big jobs as well as make small tasks easier.


Recommendations to Company

- Set variables speeds allowing users to choose which speed to use for different hardnesses of materials

- Stronger blade holder on the side

- Less grease on the gears, this would save Black and Decker money

- Make the jigsaw more difficult to take apart, so that consumers cannot get inside and void the warranty


References

Group Members

http://www.blackanddecker.com/productguide/product-details.aspx?productid=10226&toolview=2#details