Engineering Student Projects Training

Automatic drilling machine. In this project we will use five motors. First of all we try to use electronics circuit in this project. As its impossible for us to implement it using electronics circuit. So we tried it with special motors. We are trying it to buy from Delhi – motors with rpm control. Now in this project we will use one motor to move job bed forward and backward. Another motor will move drilling from on plastic pillars frames.

It will move on gear assembly to hold the frame at any stage.

Drill will be hand made. And we will keep function to move drill on attached from, so we can move frame left and right. The advantage of this project is we are doing automation without electronics, hydraulics or pneumatic. The cost of project is very low.

We will use 12v, 30 RPM motor for drilling machine. One motor will be for bed movement. Two motors for bed up and down movement. One motor  for drill left and right movement. Generally controlled motors are not available in the market. We will arrange these motors from new delhi.

Because we need motors with more torque and less speed & voltage .

DC motors

These are the motors that are commonly found in the toys and the tape recorders. These motors change the direction of rotation by changing the polarity. Most chips can’t pass enough current or voltage to spin a motor. Also, motors tend to be electrically noisy (spikes) and can slam power back into the control lines when the motor direction or speed is changed.
Specialized circuits (motor drivers) have been developed to supply motors with power and to isolate the other ICs from electrical problems. These circuits can be designed such that they can be completely separate boards, reusable from project to project.
A very popular circuit for driving DC motors (ordinary or gearhead) is called an H-bridge. It’s called that because it looks like the capital letter ‘H’ on classic schematics. The great ability of an H-bridge circuit is that the motor can be driven forward or backward at any speed, optionally using a completely independent power source.

 

 

opposite pair of transistors (Transistor One and Transistor Three) is enabled, allowing current to flow through the motor. The other pair is disabled, and can be thought of as out of the circuit.

By determining which pair of transistors is enabled, current can be made to flow in either of the two directions through the motor. Because permanent-magnet motors reverse their direction of turn when the current flow is reversed, this circuit allows bidirectional control of the motor.

Servo motors

Servo motors unlike the stepper motor it has to be controlled by the timing signal. This motor has only one coil. It is mostly used in robots for its lightweight and low power consumption. The servo motors can also be accurately rotated by the making the control signal of the servo motor high for a specific time period. Actually the servo motor will be having 3 wires where 2 are for power supply and another one is for the control signal. Driving the servomotors is so simple that you need to make the control signal high for the specific amount of time. The width of the pulse determines the output position of the shaft

 

 

Stepper motor

stepper motor have five wires . One for common supplies another four for winding purpose. By giving different signal to each we will control the stepper motor.The wires from the Logic PCB connector to the stepper motor in a TM100 Disk Drive are as followsThis kind of motor has four coils which, when energised in the correct sequence, cause the permanent magnet attached to the shaft to rotate.There are two basic step sequences. After step 4, the sequence is repeated from step 1 again.Reversing the order of the steps in a sequence will reverse the direction of rotation. This sequence produces the smoothest movement and consumes least power. Inside a Stepper Motor

The stepper motors we are concerned with are those taken out of old 5 ¼” floppy disk drives. Some of the comments below may therefore not apply in all cases…

The simplest way to think of a stepper motor is a bar magnet and four coils.

When current flows though coil “A” the magnet is attracted and moves one step to the right. Coil A is then turned off and coil “B” turned on. The magnet moves another step to the right. Coil “B” is then turned off and coil “C” turned on. The magnet moves another step to the right and so on…

A similar process occurs inside the stepper motor, but the ‘magnet’ is cylidrical and rotates inside the coils.

In order to make a stepper motor rotate you must turn on each coil in the correct sequence. The motor will continue to rotate as long as you continue the sequence. A typical code sequence would be:

feed rate.  The drill is probably one of the original machining processes and is the most widely used.

Drilling machine -important features/dimensions

Pillar Drill

The pillar drill has the same features as the bench drill.  This drill is however free standing and is of a far heavier construction able to take larger drills.  The larger drills normally have taper shanks which are located within a taper bore in the spindle end.  These tapers are standardised as morse tapers.

Radial Arm Drill

The radial drill is a free standing and the workpiece is clamped in position on the base.   The drill head is positioned using motorised drives.

Notes on Selection of Drilling Machines

Normal pillar drilling machines (Drill Press) are specified basically by the size of hole the machine can drill in Mild Steel i.e a 16mm machine can drill holes upto and including 16mm dia in mild steel.   The speed range of a drilling machine is related to the size e.g. machines for small holes down to 1mm can have speed ranges up to 8000rpm.   Larger drilling machines more suited for drilling holes. up to 25mm will have a more limited range.  A machine which is used to drill larger holes ( >15mm) is not generally suitable for drilling small diameter holes (< 1 mm).  Smaller machines are provided with permanent chucks whilst larger machines gnerally include morse tapers for fixing the drills.

Most pillar drills are manually fed using a rotating lever driving the vertical motion of the spindle.  Larger machines can have power drives feeds.

A belt driven spindle is often a convenient low cost option but there is a tendency in modern times to use geared /inverter drives.

When drilling holes in a material a number of factors should be considered including

Drilling Machines/ Machining Centres

Types of Drills Bits

Drill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes.

This article describes the types of drill bits in terms of the design of the cutter. The other end of the drill bit, the shank, is described in the drill bit shank article. Drill bits come in standard sizes, described in the drill bit sizes article. A comprehensive drill and tap size chart lists metric and imperial sized drills alongside the required screw tap sizes.

The term drill can refer to a drilling machine, or can refer to a drill bit for use in a drilling machine. In this article, for clarity, drill bit or bit is used throughout to refer to a bit for use in a drilling machine, and drill refers always to a drilling machine.

Components required:

Gears assembly

Plastic Rods or plates

Ply board

Copper clad board

Applications

•  for industrial automation

• for robotics

• for biomedical machines

• for military application

• for construction