Group 1 - Black & Decker Drill

Executive Summary

The Black & Decker® DR202 3/8” Variable Speed/Reversible Drill is a must-have tool for almost any project. This six-pound power tool is light enough to be used for the everyday 'do it yourself' tasks while the five-amp motor is powerful enough for professional carpentry and construction jobs.

The main purpose of the DR202 is to drive and remove screws, and drill holes through various materials such as dry wall, steel, soft and hard woods, and plastics. It operates by taking electrical energy supplied by a standard household power outlet which it converts to rotational energy used within the motor. The rotational energy is transferred to mechanical energy, moving the gears within the motor, which supplies the torque to move the bit. It has variable speed: the farther the trigger is depressed, the higher the speed of the drill. The drill can also be locked for continuous use by squeezing the trigger while pushing in on the trigger lock mechanism. Additionally, the drill has a 8’ electrical cord with a two-prong plug. It has a direction reverse switch: push the switch to the right for forward rotation (clockwise rotation), push the switch to the left for reverse rotation (counterclockwise). The drill has a fifteen-position keyless chuck and a convenient bit holder located on top of the drill.

Side view of Black and Decker DR202 Drill	Top view of Black and Decker DR202 Drill	Front view of Black and Decker DR202 Drill

Gate 1: Request For Proposal

The below link navigates to the Gate 1: Request For Proposal page which outlines:

Project Purpose
Group Members' Backgrounds
Proposed Time Management
Group Dynamic Analysis
Pre-Dissection Analysis

Request of Proposal Page

Gate 2: Preliminary Design Review

The below link navigates to the Gate 2: Preliminary Design Review page which outlines:

Gate 2 Purpose
Cause For Corrective Action
Parts List
Product Dissection Plan
Post-Dissection Analysis

Preliminary Design Review Page

Gate 3: Coordination Review

The below link navigates to the Gate 3: Coordination Review page which outlines:

Gate 3 Purpose
Cause For Corrective Action
Component Summary
Design Revisions
Solid Modeled Assembly
Engineering Analysis

Coordination Review Page

Purpose

Gate 4 is the final project review in which the reassembly process is analyzed.

Product Reassembly Plan

The product's reassembly is best approached by reassembling each "Product Reassembly By Steps" table seen below details a step-by-step process for reassembling the drill.

It is recommended that photographs of parts, assemblies, and stages be used as aides during the disassembly process.

Tool required:

Torx #15 screw driver
Flat-head screwdriver
Needle-nose pliers

Armature Assembly Reassembly Steps
Step	Description	Tool Required	Time Required	Difficulty (1-3)	Step Photograph
1	Slide red washer over rear end of the armature.	Hands	0:15	1	File:.JPG Red washer replaced
2	Slide heat sink over rear end of the armature. The fin side of the heat sink should be closes to the armature core.	Hands	0:15	1	File:.JPG Smooth side of the heat sink File:.JPG Fin side of the heat sink File:.JPG Heat sink replaced
3	Slide small metalic washer over read end of the armature.	Hands	0:15	1	File:.JPG Metalic washer replaced
4	Replace retaining ring to secure all of the components on the end of the armature. Note: The retaining ring is easily replaced by positioning the open side of the "C" shaped clamp against the armature and then squeezing the ring into place with pliers.	Hands and pliers	0:15	1	File:.JPG Retaining ring replaced

Motor Assembly Reassembly Steps
Step	Description	Tool Required	Time Required	Difficulty (1-3)	Step Photograph
1	Slide reverse ring and field together and then secure the two pieces with the 1 7/8"torx screws. Note: The reverse ring can be combined with the field in two ways. To easily identify the proper orientation hold the field in one hand with the serial numbers on top and slide the reverse ring into position from the left such that the "B" is further away.	Hands and torx 15	1:15	2	File:JPG
2	Slide retaining brushes into place ensuring that the flat spring fits into rear end of the brushes.	Hands	0:15	1	File:.JPG Retaining brushes replaced
3	Compress retaining brushes with a flat-head screwdriver and slide the armature inside.	Flat-head screwdriver	:20	1	File:JPG Completed Motor Assembly

Gearbox Assembly Reassembly Steps
Step	Description	Tool Required	Time Required	Difficulty (1-3)	Step Photograph
1	Slide pinion into the front bearing meshing it with the gear.	Hands	0:15	1	File:.JPG Pinion and front bearing reassembly
2	Slide rear bearing onto the rear of the pinion and gear prongs.	Hands	0:15	1	File:.JPG Completed gearbox assembly

Internal Assembly Reassembly Steps
1	Slide the geared end of the motor assembly into the center of the rear bearing.	Hands	0:15	1	File:.JPG Combined motor assembly with gearbox assembly
2	Reconnect power wires into the rear of the reverse ring. Note: The black wire enters the reverse ring terminal marked with a "B" and the white wire enters the unmarked terminal.	Hands	0:15	1	File:.JPG Completed internal assembly

Total reassembly time: 10 minutes, 50 seconds.
*Note: the break down for the difficulty levels are as follows:

1 = easy; requiring little effort.
2 = medium; some prior thinking required.
3 = hard; required multiple attempts; two people recommended.

Post-Reassembly Analysis

Below are a few sample questions that address the final condition of the product, disassembly/reassembly differences and further product recommendations:

- Does your product run the same as it did before you disassembled it?

The product runs the same as it did before the disassembly process. We attribute the successful disassembly and reassembly of the process to the detailed notes and photography making it easy to retrace the steps.

- What were the differences between the disassembly/reassembly processes?

The main differences between the disassembly and the reassembly processes were the attention to detail needed. For example, it's easy to remove all of the small washer, the heat sink, and the red washer, but when returning the armature to its original form, the person doing the reassembly needs to know the order and the orientation of the heat sink so that the product will fit in the drill housing properly. similarly, when combining the field and the reverse ring, there are many opprotunities for mistakes: wire placement and the proper orientation of the reverse ring on the field itself.

Taking good notes and paying close attention to each piece prior to removing it is allowed the group to reassemble the entire product.

Different tools used:

Needle-nose pliers

- What additional recommendations would the group make at the product level

The only area of the drill that the group felt could benefit from modification was the field and reverse ring. The first modification that could be made would be to implement a notch into the field and a protrusion on the reverse ring such that the two could only fit together one way. This would prevent the two from being reassemble improperly. The second modification would be to replace the current system of connecting the wires individually into the reverse ring with a single plug in system which would further reassmbly confussion.reduce faughlty reconstruction of the motor assembly

Contact Us

Group 1 E-mail

References

Gate 1:

[1] "Model # DR202 Spec. Sheet." Toolbarn.com. 06 OCT 2009 <http://www.toolbarn.com/blackdecker-dr202.html>
[2] “How Stuff Works: Power Drill.” How Stuff Works. 05 Oct 2009 <http://home.howstuffworks.com/power-drill.htm>

Gate 2:

[1] "DeWalt Service Technical Information" dewaltservicenet.com. 12 OCT 2009 <http://www.dewaltservicenet.com/Products/DocumentViewPDF.aspx?productid=33258&typeId=8795&documentId=21976&AspxAutoDetectCookieSupport=1>

Gate 3:

[1] "DeWalt Service Technical Information" dewaltservicenet.com. 12 OCT 2009 <http://www.dewaltservicenet.com/Products/DocumentViewPDF.aspx?productid=33258&typeId=8795&documentId=21976&AspxAutoDetectCookieSupport=1>

Housing Reassembly Steps
Step	Description	Tool Required	Time Required	Difficulty (1-3)	Step Photograph
1	Seat internal assembly into the groves of the drill housing. Note: Ensure that the serial numbers on the field are towards the top of the drill housing and that the retaining brushes on the armature are still on the copper track. The internal assembly should slide into place with minimal effort.	Hands	2:45	2	File:.JPG Internal assembly seated inside of drill housing
2	Replace VS control unit. Note: The triangular shaped locking mechanism should slide freely into the hole on the drill housing.	Hands	0:15	1	File:.JPG Completed internal assembly
3	Slide power cord into its location	Hands	0:15	1	File:.JPG Completed internal assembly
4	Secure power cord with cord clap and two screws	Hands and Trox 15	0:15	1	File:.JPG Completed internal assembly
5	Slide cap and bit holder into place on the top of the drill	Hands	0:45	1	File:.JPG Completed internal assembly
6	Replace housing cover over and secure with screws	Hands and Trox 15	2:45	1	File:.JPG Completed internal assembly