Automatic Tool Changer

The full form of ATC is automatic tool changer it is used in CNC machines for changing tool automatically which helps to reduce the cycle time. If we think that tool will be changed manually then it will take more time and it is harmful to operator so in modern technology automatic tool changer is used the tools are fitted in the tool magazine as per the required operation the tool which change the tool from tool magazine and change it automatically so tool changing time will be reduced.

Mainly there are two types of ATC are:-

1) Drum Type

2) Chain Type

Drum Type:-

For holding small number of tools usually not more than 30, it is stored on the periphery of drum and tool search speed is faster in this type of ATC.

Chain Type:-

For more number of tools (40 or more), tools search speed will be less in this type of ATC. 

Advantages of ATC:-

1) Lines changed in seconds instead of hours

2) Increase operator safety by changing tool automatically

3) Changes the tool in seconds of time 

4) Increase flexibility

Figure of Automatic Tool Changer is shown below:-

Open loop & Closed loop system

Open loop system

As we know in CNC machine various operations are done the basic process is we give input like raw material then it will do various process on it and finally we will get the output here we will understand about open loop system in open loop system the process is same like Input, process & output in open loop system there is not a feedback device so if the output is ready and if it is accurate or not or any problem came in it we will not be able to know in open loop system because there is no feedback device this is known as open loop system. Figure of open loop system is shown below.

As shown in figure there is no feedback device this is known as open loop control system.

Closed loop system

The main thing in closed loop system is that there is a feedback device so if any problem during operation or in output the feedback device will give feedback to the error signal so we can make changes in it so now we we get the accurate product without any defect this is know as closed loop system. Figure of closed loop system is shown below.

In this figure we can see that there is a feedback device that goes to error signal so we are able to know that some problem is there and we can correct it this is known as closed loop systems.

Gym Equipments

Fitness is a thing every person should be wearied about but in this fast life most of peoples doesn’t have the to go to the gym for 1or2 hours so the perfect solution of this problem is to get a good gym set with some dumbbells and weight plates. 
So, the under given gym set is a perfect set in my opinion for a person who don’t want to purchase membership of gym. But want to make some muscle mass but keep in mind muscularity don’t come only with weight training your diet also should be proper and systematic.
Now tells talk about this product and what content it have: 
1. It has plates of 30kg 
2. 1 5ft long Rod 
3. 1 3ft curl Rod
4. 2 rod for dumbbells
5. It also got gym bag, Leather gym gloves, skipping rope, hand gripper pair LINK GIVEN BELOW
https://lm.facebook.com/l.php?u=http%3A%2F%2Famzn.to%2F2gId9zP&h=ATMqaHYiI3uHANqk8enDnueq6iDp09qFlRt6s_NXmBn44tE9vQjIJPZTW5x9_JM5vykiuYheyoQjCR_hJNo2HA0VDwG5YXBUpZfiwfp0MIOkGGjZN-UuDcGY636NQmCti4bor0DQr_xqJB49&enc=AZPlzQZ6w1_m5sIggsnk8ply-QKBM_PKPmDtDp1qiUJz2hc-CANs9bcCyPrUY6QcRwMrABw0X4ofXz15nNdN378cuHx_M4WewrjCSiveTgsiPic0DlH17QOKUf6GjVrOYDfYDMu_LvNs6SEbqVORs12Rdv6q1A10GFsaRmm6cRt9XGdleVoTpMzVv02KJIkou_w&s=1

Gear Tooth Terminology

Pitch Circle :

Pitch circle is the apparent circle that two gears can be taken like smooth cylinders rolling without friction.

Addendum Circle :

Addendum circle is the outer most profile circle of a gear. Addendum is the radial distance between the pitch circle and the addendum circle.

Dedendum Circle :

Dedendum circle is the inner most profile circle. Dedendum is the radial distance between the pitch circle and the dedendum circle.

Clearance :

Clearance is the radial distance from top of the tooth to the bottom of the tooth space in the mating gear.

Backlash :

Backlash is the tangential space between teeth of mating gears at pitch circles.

Full Depth :

Full depth is sum of the addendum and the dedendum.

Face Width :

Face width is length of tooth parallel to axes.

Diametral Pitch :

Diametral pitch (p) is the number of teeth per unit volume.
p =  (Number of Teeth) / (Diameter of Pitch circle)

Module :

Module (m) is the inverse of diametral pitch.

m = 1/p

Circular Pitch :

Circular pitch is the space in pitch circle used by each teeth.

Gear Ratio :

Gear ratio is numbers of teeth of larger gear to smaller gear.

Pressure Line :

Pressure line is the common normal at the point of contact of mating gears along which the driving tooth exerts force on the driven tooth.

Pressure Angle :

Pressure angle is the angle between the pressure line and common tangent to pitch circles. It is also called angle of obliquity. high pressure angle requires wider base and stronger teeth.

Pitch Angle :

Pitch angle is the angle captured by a tooth.
Pitch angle = 360/T

Contact Ratio :

Contact ratio is angle of angle of action and pitch angle.

Path of Approach :

Path of approach is the distance along the pressure line traveled by the contact point from the point of engagement to the pitch point.

Path of Recess :

Path of recess is the distance traveled along the pressure line by the contact point from the pitch point to the path of disengagement.

Path of Contact :

Patch of contact is the sum of path of approach and path of recess.

Arc of Approach :

Arc of approach is the distance traveled by a point on either pitch circle of the two wheels from the point of engagement to the pitch.

Arc of Recess :

Arc of recess is the distance traveled by a point on either pitch circle of the two wheels from the point to the point of disengagement.

Arc of Contact :

Arc of contact is the distance traveled by a point on either pitch circle of the two wheels during the period of contact of a pair of teeth.

Angle of Action :

Angle of action is the angle turned by a gear during arc of contact.

Heat Exchanger

A heat exchanger is a device that is used to transfer thermal energy between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact.

It provides a relatively large area of heat transfer for a given volume of the equipment. The construction also caters for easy cleaning and maintenance of equipment.

They are widely used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, sewage treatment. A classic example of heat exchanger is radiator coil in a car. It cools the engine coolant and preheated the incoming air.

The word heat exchanger really applies to all types of equipment in which heat is exchanged but is often used specifically to denote equipment in which heat is exchanged between two process streams.