Contents
- How does a Vacuum Pick-up System work?
- How much weight can be picked up with a probe/cup?
- What is the difference between the pumped and bulb systems?
- What is the difference between the plugin and battery operated systems?
- How do I pick up and release the part?
- Which of these systems are ESD safe?
- Do all probes and probe/cup combinations fit all systems
- How do I select a probe?
- How do I select a cup diameter?
- What are the cup material options?
- What are the options if a part is too heavy or not flat enough to be handled by a vacuum pick-up system?
- Is there another pump that could be use as a vacuum source to achieve more lifting force?
How does a Vacuum Pick-up System work?
A vacuum pick-up tool works by applying a vacuum at the end of a probe/cup that is in intimate contact with substrate being picked up. The difference in pressure between atmospheric pressure and the vacuum applied over the contact area provides the lifting force.
How much weight can be picked up with a probe/cup?
Since the lifting force relies on the difference between atmospheric pressure on one side of the substrate and the vacuum pressure on the cup side, the lifting force is a function of the contact area of the probe/cup/wand and the vacuum level generated by the system. One also should apply a safety factor of 1.5-2 resulting from surface roughness of the substrate, g force moving the substrate, substrate cleanliness and friction coefficient. These factors result in a practical lifting 1 g/sqmm probe/cup area for the Vacuum Pick-up Systems and 4.4 g/sqmm of wand area for the Vacuum Handling Tools for Wafers.
What is the difference between the pumped and bulb systems?
We offer 2 types of vacuum pick-up systems, Continuous and Bulb. The continuous systems use a small vacuum pump to continuously provide a vacuum to the probe when activated. Both the Bulb types 528-16 and 528-2 contain a rubber bulb that when compressed expels air and when released sucks to form a temporary vacuum much like a pipette bulb. Both provide initial lifting capacity similar to the continuous systems but any leakage will result in lessening of the lifting force. These bulb type vacuum pickup tools will pick up and transfer samples with flat surfaces like silicon, glass and polished carbon substrates.
What is the difference between the plug-in and battery operated systems?
The plug-in pump must be connected to an electrical outlet. This tethers the pick-up pen to a workstation during operation. Vacuum tubing connects the pump body to the pick-up pen. The battery operated systems have the pump integrated in the pickup pen so are completely mobile.
How do I pick up and release the part?
On the PELCO® Vacuum Pick-Up with Pump system, you place and hold your finger over the hole at the end of the Pick-Up pen to apply the vacuum to the probe, and remove your finger to release the vacuum. On the Battery Powered Vacuum Pick-Up Tool you apply vacuum by pressing and holding the power button and stop pressing the button to release the vacuum. On the Pen-Vac™ bulb systems, vacuum is generated by pressing and releasing the vacuum push bar. Pressing it again will release the part. On the Porta-Wand® wafer vacuum tools there is a button switch on the handle that is pressed to apply and release the vacuum.
Which of these systems are ESD safe?
The systems that state they are ESD safe, all of the metal probes, and the ESD vacuum cups provide a lower resistance path to prevent charge build up when used in conjunction with proper operator grounding wrist strap.
Do all probes and cup/probe combinations fit all systems?
Yes, all of the systems on the “Vacuum Pick-Up Systems, Probes and Cups” page fit all of the vacuum tips and probes. Each tool has a male-taper Luer tip that fits the female-taper Luer fitting at the end of every metal tip/probe.
How do I select a probe?
Cups are attached to the end of a probe. Probes come in different lengths and straight or bent. This selection is based on ergonomic considerations. Most users find that a bent probe is more ergonomic since the pick-up pen is naturally held at a writing angle where a bent probe places the tip parallel to the work surface for easier pickup. A straight probe requires that the pick-up pen is held perpendicular to the work surface. If the operation requires a manipulation of the part for example in an inspection operation, then a straight probe may be a better option. A longer probe often improves visibility by placing the cup further from the pen.
How do I select a cup diameter?
For small parts select a cup with the largest diameter that can be easily positioned over the part without hanging over the edge. This will give the largest lifting force as explained above. For larger parts like a coverslip, select a cup with a large enough diameter to allow you to lift the part.
What are the cup material options?
Black Buna-N is ESD safe non-marking material for standard temperature, -20°C to +120°C / -4°F to +248°F. ESD specifications: Resistivity 108-1011 ohms.
Clear Silicone is a non-marking material for high temperature, -55°C to +250°C / -67°F to +482°F. Not ESD safe.
Small parts ESD safe Delrin® tips are for items as small as 100 microns.
What are the options if a part is too heavy or not flat enough to be handled by a vacuum pick-up system?
Since the smaller the vacuum contact area the smaller the lifting capacity, this is sometimes the limitation of using a vacuum system on small heavy objects. Some objects have a surface topography that is too rough to allow the probe/cup to form a vacuum seal. In these cases tweezers are a better option and PELCO® Pro Reverse (self closing) Tweezers or ESD Safe, PVDF Tipped Tweezers, ESD Safe Wafer Tweezers that will grip when released may be a good option. These often are less fatiguing than standard tweezers, particularly during long inspections. These apply a repeatable pressure on the tips whereas an operator may squeeze a standard tweezer too hard, which may damage the part.
Is there another pump that could be used as a vacuum source to achieve more lifting force?
Our Vacuum Diaphragm Pump (#3436) is an optional vacuum source. Its maximum vacuum is -25.5"Hg or 12.5 psi for a practical lifting force including safety factor of 5 g/sqmm.
One would have to adapt the port to attach a pick-up pen and probe using a 1/4" NPT to 1/8" barbed fitting (customer supplied) on the inlet, along with the items below and your preferred probe.
#520-13 Silicone Vacuum Tubing 1/8" ID x 1/16 wall, 4' L
#520-12 Pick-up Pen, 9.2 x 127mm, barbed fitting for 1/8" I.D. hose
The inlet flow can be regulated with the valve located behind the vacuum gauge and it is an oilless pump so will not contaminate your product.