## Vacuum Foam Gripper

### Vacuum foam gripper calculation and how to choose right vacuum foam gripper theoritical and calculation as enclosed. ## Vacuum Foam Gripper Calculation

vacuum foam gripper calculation is important for how to know about foam pad cell force and how many vacuum foam gripper to use in vacuum handling system.

#### Sample Theoretical Force Calculation

Vacuum level = -300 mbar
cell width = 11 mm
cell lenght = 13 mm
F = PA
= abs| – 300 / 100 | * 0.785 * ( 1.1 * 1.3 ) cm2
= 3.37 N/Cell #### Number of hitting cell

N = number of hitting cell
W = workpiece width
w = cell width
c = overlap (2 – 8)
d = distance cell to cell
N = (W – w – ( 2 * c )) / d
= (150 – 11 – (2 * 4)) / 4.5
= 29 hitting cells

#### Need Parallel Gripper

m = workpiece weight
sf = safety factor
n = number of hitting cell
Ft = theoretical force
parallel gripper = (m * sf * 9.81) / ( n * Ft)
= ( 10 * 2 * 9.81 ) / ( 29 * 3.37)
= 2 grippers ## Vacuum Foam Pitch and Size

The main information we use is weight per surface. We look at each size and compare with weight to see if the pick-up capacity is enough. Then, we compare with the theoretical pick-up capacity of each pitch. This is why we ask for the sizes of products and their weight.

#### For Example Case

For carton box
wide = 150 mm (5.9 in)
long =  150 mm (5.9 in)
tall = 100 mm (3.94 in)
weight = 5kg (11.02 lbs).
Surface in contact with the gripper is 0.15 x 0.15 = 0.0225 m2. Weight per m² is 222 kg/m2 (489.43 lbs/m2)
which start to be heavy. So we need P20 mm.
If the same box is 4 kg (8.82 lbs) instead of 5 kg (11.02 lbs)
we can use P28 which is 50% less valves (lower price) and lower turbine power.
If the same box is 3 kg (6.61 lbs)
we can use P40 which is 4 times less valves than P20 so again much cheaper than P20 and cheaper than P28 and smaller blower required.

#### An other parameter: the minimum size of the products

For small ones, it is impossible to use P40 as there will not be enough foam holes on the top of the products.

## Theory of vacuum systems

### This blog have information for vacuum systems history, physical, calculation and design. ## HISTORY OF VACUUM TECHNOLOGY

Vacuum Technology Origin and definition of vacuum
Original of the word
Latin “vacuus” = empty / free
Definition according to DIN 28400

Vacuum is the state of a gas, whose particle-number density is lower than the one of the atmosphere on the earth‘s surface.
The state of a gas can be called as vacuum, when its air pressure is lower than the atmospheric air pressure.

#### Meaning of the word vacuum:

Colloquial: Vacuum is matter-free space.
Technical, Physical: Vacuum specifies the State of a Fluid in a volume at a pressure, that is considerably lower than the pressure of the atmosphere at normal circumstances.
Quant physics: The state of vacuum of an element is the state where it has the smallest energy. ## Break-through in the proof of vacuum

Evangelista Torricelli (1608 – 1647)
Student of Galileo Galilei

#### the first proof of vacuum ## Experiment in 1643

A brimful filled with mercury glass tube is put up-side-dow into a bowl that is filled with mercury
Notice: Silvery column falls down a little bit and
always levels off independently of the length of the tube on the same level
Above the mercury level there is free room
– the first experimentally created vacuum

#### What is Vacuum? ## Impressive confirmation of the properties of vacuum

Otto von Guericke (1602 – 1686)
Diplomat and mayor

#### Confirm testing with vacuum ## Experiment in 1654 (1656 in Magdeburg)

Otto von Guericke places 2 hollow hemispheres out of cooper (diameter ca. 50 cm) on each other and seals the hemispheres. Afterwards he evacuates the space inside with a self-invented
piston pump. The ambient pressure presses the two hemispheres together. 16 horses (2 teams with 8 horses) weren’t able to separate the two hemispheres.

#### Powerfull of vacuum. diameter 50 cm.

## Physical properties of vacuum

### for vacuum properties we can find example as enclosed. ## No sound propagation

The sound propagation requires a material medium to devolve the sound waves.

#### sound cannot avialable in vacuum ## Reduction of heat flow and heat conduction

No medium existent to carry the heat flow.

#### Heat conduction ## Lowering of boiling point

The boiling point of a fluid is reached, when the vapor pressure is equal to the external pressure

## Vacuum Systems Design

### For vacuum systems design and calculation we need to know paramerter and what we need to handling and what is system want to pick and place. ## How to calculate weight for workpieces in vacuum handling systems

workpiece is very importance to calculate all equipment in vacuum sysytems design so we want to know basic parameter to calculate or get real weight to choose right another vacuum equipment

#### Example wood workpiece

find dimension and density

m = L x W x H x p
m = Weight (kg)
L = Length (m)
W = Width (m)
H = Height (m)
p = Density of workpiece (kg/m3)

Example

m = 3.05 m x 0.05 m x 0.008 m x 1260 kg/m3

m = 1.54 kg How to defind vacuum pad, vacuum cup, suction pad, suction cup or another customer call but they use the same theory to define.

#### Basic Calculation for Vacuum Cups

in case for define diameter for vacuum cup as below. Force lift up and move horizantal

Load Condition - Vacuum cups direction and force direction.

Fomular :

d = 1.12 √(m * S) / (Pu * n)

d = diameter cm

m = mass kg.

S = safety factor

Pu = vacuum level bar

n = number of vacuum cup Workpiece turn 90 degree or turn over workpiece

Load Condition - Vacuum cups direction and force direction.

Fomular :

d = 1.12 √(m * S) / (Pu * n * u)

d = diameter cm

m = mass kg.

S = safety factor

Pu = vacuum level bar

n = number of vacuum cup

u = coefficiency factor ## For Exsample

We want to use vacuum cup for metal sheet and use 1.5 bellow vacuum cup

Metal sheet m = 50 kg.

vacuum level Pu = – 0.4 bar

number of vacuum cup n = 4

Coefficiency u = 0.5

Safety factor S = 2

Use Formular

d = 1.12 √(m * S) / (Pu * n * u)

d = 1.12 √(50 * 2) / (0.4 * 4 * 0.5)

d = 12.5 mm

d = 125 mm ## Sample Picture for Vacuum cup

for final choose vacuum cup we can choose

#### for metal sheet application

for another principle we should select type of material for suiable to use with our application in picture is vacuum cup in PU they are suitable for wear resistanc and long life to you with stamping or press shop application in automotive industry.

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