The Pneumatic Robot is the simplest and least expensive of all robots. It is fast and very repeatable and is the simplest to program.
The air powered robot is a very simple device, that uses well proven technology to produce a very efficient, pick and place machine.
All axes are powered with an air cylinder and have a fixed stroke, that is non-programmable. This makes for a very cost effective solution, that is very accurate and repeatable.
The Pneumatic robot shown here is built using Festo modular components. Using such units reduces the technical risk and is very cost effective.
Assembly automation uses a lot of these machines, sometimes in conjunction with vibratory bowl feeders and in this application are commonly referred to as "pick and place units".
This photo shows the Festo Linear Module HMP. This unit is used as the horizontal element in the pneumatic robot shown in the above photograph. (Actually the unit shown in the photo Is no longer available and the HMP unit has replaced it)
These units are available in bore sizes of 16mm(0.63in.), 20mm(.79in),25mm(.98in) and 32mm(1,26in).
Strokes are up to a maximum of 400mm(15.75in).
Repeatability is quoted as 0.01mm(0.0004in) and speed is adjustable (Via flow control valves) up to a maximum of 1.2M per second.(4 ft/second).
The unit contains shock absorbers and micrometer adjusters for end of stroke, as well as proximity switches to detect end positions.
Options available are intermediate stops and a clamping unit.
The shock absorber, moves with the unit and the adjuster can be coarsely positioned in the groove and finely adjusted with the micrometer adjustment.
These stops can be activated on the forward or reverse stroke. Multiple units are possible. One favorite application of mine is to use them to reject bad parts, on a pneumatic robot unload.
The "Normal" stoke for good parts is the shorter distance and when a rejected part is detected, then the longer stroke is used and the part is placed on a reject conveyor or chute.
This unit is useful to use to clamp the position of the unit, as a safety device. In the event of air shut off, the clamp is activated and prevents any movement of the axis.
For full details of the Festo HMP modules, take a look at this page.
Here we will consider the Festo mini-slide SLT. This unit has twin air cylinders and is available in bore sizes from 6mm (0.24in.) to 25mm (0.98in.). Strokes are up to 200mm(7.87in.)
They will bolt, via an adapter plate, to the front of the HMP unit.
Shock absorbers and proximity switches are built in. For full details take a look at this page-Festo Mini-Slides SLT, SLS, SLF.
The Festo HGRT radial gripper can be adjusted in opening angle ftom 0 to 180 degrees. The grip fingers are custom designed to suit the part being handled.
The part can be gripped internally or externally and there are 6 sizes available from 16mm(0.63in.) air cylinder bore to 50mm(1.97in.).
Both single acting and double acting types are available and spring assist can be added, that allows a part to remain gripped, when air is disconnected.
Proximity switches can be added to sense finger open and close.
For full details of the Festo HGFT Radial Gripper, look at this page.
Details of other Robot Grippers are shown on this page.
Sometimes it is necessary to rotate the part, from the "Pick" point and before the pneumatic robot reaches the 'Place" point.
Rotary units are available that can rotate the gripper.
Rotation angles can be adjusted, up to 360 degrees and twin cylinders and rack and pinions are adjusted and dampened by shock absorbers.
These units can be mounted between the end of the vertical axis and the gripper. Adapter plates are available for this purpose.
For more information on the Festo DRQD Rotary Units, visit this page.
Pneumatic Pick and Place Equipment can be very cost effective and efficient in many applications.
Where the axes strokes are all fixed they make a very accurate and repeatable alternative. The modular design means that as many axes as necessary can be used.
At the start of a project, when the pick and place vendor has been selected, the first part of the job is to download all the drawing software required, from the vendor's web site. All of them offer both 2D and 3D versions.
Control of the pneumatic robot is generally via a PLC. Early and close contact with the programmer is highly recommended. Logic should always be of the "End Point" type. I.E. the proximity switch at the end of a stroke initiates the next action in the sequence. This way the sequence is assured and if a problem arises then it is usually easier to diagnose.
Generally allow at least 1 second minimum per action. The modules can operate a lot faster, but long life is assured if strokes are on the slow side and not banging and shaking around!