Perfecdos precision micro dispensing systems

Application of grease to shaft

FAQ's

 

Close-up view of PDos X1 Nozzle wih Heater

 

  What is Contactless Dispensing Technology ?
 

  What advantages does contactless dispensing offer ?
 

  Where is contactless dispensing put to use ?
 

  What's required to operate a Perfecdos micro dispensing system ?
 

  Which materials are dispensable with a Perfecdos micro dispense system ?
 

  What dispensing results are technically feasible ?
 

  What equipment is necessary to correctly operate the valve functions ?
 

  What additional equipment is available to compliment the Perfecdos micro dispensing system ?
 

  What interchangeable spare parts are there for the valve ?
 

  What has to be observed during maintenance ?

 


 

What is Contactless Dispensing Technology ?

Perfecdos adopts a dispensing technology known as jetting, where there is no contact between the dispensing valve and the component being dispensed onto. The dispensed medium is "shot" out of the nozzle and crosses the distance between the nozzle and the target component in free flight, before it lands precisely on the component. Even the smallest amounts of media, with viscosities ranging from low to paste like materials, can be accurately and repeatedly applied simply, quickly and precisely with Perfecdos dispensing technology.

An example from our experience: the gluing of minute components (SMD components) on to circuit boards and substrates. The component carrier must be positioned completely flat.

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What advantages does contactless dispensing offer ?

  • Time saving (no positioning movement and application of the material onto the component part)
  • High dispensing frequency
  • High dispensing accuracy
  • Close to volumetric dispensing process
  • Very repeatable
  • Dispensing volumes can be adjusted easily and safely
  • No contact with the component part (prevents damage or contamination of the part or the nozzle, respectively)
  • Part tolerances and position tolerances are not an issue
  • Easier positioning of the part
  • Part typography and surface finish not an issue
  • Consistent drop formation of the dispensing material

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Where is contactless dispensing put to use ?

Perfecdos dispensing technology is suited to industrial mass production as well as manual work and laboratory processes respectively and is being employed extensively in the following areas:

  • Electronic Industry
  • Solar Industry
  • Mechanical Engineering
  • Automotive Industry
  • Aerospace
  • Packaging Industry
  • Furniture Industry
  • Medical Engineering
  • Cosmetics Industry
  • Food Industry

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What's required to operate a Perfecdos micro dispensing system ?

There are 2 main components to a Perfecdos micro dispensing system - they are:

  • Micro Dispensing Valve
  • Micro Dispensing Control System
  • Material Supply Source

The micro dispensing valve operates on compressed air controlled by a precision electro-pneumatic solenoid.  In order to control the solenoid to give the correct electrical characteristics (24VDC / 2.5A square wave impulse) a controller is required - there are several options available (click here).

Material supply to the micro dispensing valve has to be supplied under pressure - this can provided by applying pressure to a supply cartridge or pressurised supply tank.

The VC1 Controller offers full control of the electrical impulse time, pause time and frequency.  In addition, where a heater is fitted, it also controls the nozzle temperature.

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Which materials are dispensable with a Perfecdos micro dispense system ?

Through contactless dispensing technology, materials with viscosities ranging from water to pastes can be dispensed with ease. Perfecdos is continuously expanding its selection of dispensable material groups.

Dispensable material groups

  • Water
  • Solvents such as acetone, alcohol
  • Fluxes
  • Oils
  • Silicones 
  • Adhesives
  • Greases
  • Colours
  • And many more....
     

What viscosities can be dispensed ?

The spectrum of dispensable viscosities ranges from low viscosity, watery (0.5 mPas) to high viscosity, paste and thixotropic (up to 500,000 mPas). The viscosity of most materials depends on temperature. In many cases the viscosity can be reduced and held at a constant level through heating, which more often than not, has a positive outcome in the dispensing results.

Which properties influence the contactless dispensing ?

The following factors influence how well a material can be dispensed:

  • Viscosity
  • Flow behaviour (flows well or is stringy)
  • Thixotropic behaviour (shear-thinning)
  • Stability (does the medium change over time)
  • Anaerobic curing mechanism (Super Glues)
  • Fillers
  • Filling levels
  • Manner and state of the fillers (hard, soft, large, small)

Simple to challenging dispensing materials

A wide range of materials can be applied very simply through contactless dispensing, such as UV-Adhesives, Unfilled Epoxies, Oils, Greases etc. In comparison the dispensing parameters for filled, stringy or thixotropic (shear thinning) materials should be meticulously investigated through preliminary tests.

Preliminary dispensing tests

Perfecdos recommends performing preliminary dispensing tests with the respective material to ensure the material can be dispensed as required.

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What dispensing results are technically feasible ?

What drop size and line width are feasible ?

The possible sizes of drops, beads and lines are conditional on the medium, the component surface and the valve configurations. Within these conditions the following dispensing results are achievable:

  • Droplet size from 1 nL / 0.25mm diameter upwards
  • Line width from 0.25mm upwards

From what distance can the medium be applied ?

Contactless dispensing with a Perfecdos micro dispensing valve enables a dispensing distance from 2mm to 50mm between the valve and the part (depending on the dispensing results). In most cases the distance in normally between 2mm and 10mm. In exceptional cases distances from 40mm to 60mm can be achieved. With increasing distances, the precision of the dispensing results will suffer due to external influences such as air movement or electrostatic charge, the positioning tolerance increases and the drop can display irregularities. These effects are strongly influenced by the dispensing medium. A rule of thumb is to keep the dispensing distance as small as possible. The most ideal distances are from 2mm to 5mm between the nozzle and the object.

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What equipment is necessary to correctly operate the valve functions ?


VC1 Controller Multifunctional for every mode of operation

The VC1 Controller is an especially safe and convenient way to regulate the PDos X1 valve. Peripheral appliances like heater controls are integrated. The VC1 is especially suited for laboratory use and manual work stations. With this device it is very easy to find the most suitable basic settings for optimal dispensing results.

Precision Air Pressure Regulators

To accurately control the dispense valve function and fluid delivery, you will need 2 x precision air pressure regulators
supplied with dry, filtered (to 40 m) & oil-free compressed air. Both pressure regulators need to be capable of delivering 4 - 8 bar (55 - 115 PSI) air pressure and be fast responding.

To ensure that there is sufficient pressurised air at the correct pressure to supply the dispense valve we also recommend installing a buffer tank of at least 0.4 litres capacity as close as possible to the dispense valve.

The other air pressure regulator is used to control the air pressure on the material feed (cartridge or pressure vessel) and needs to be constant to ensure consistent results.

Suitable PLC

It may be possible to use a suitable PLC capable of generating the correct 2ms 24VDC 2.5A square waveform output signal - a lower cost option for integrating the Perfecdos micro dispense valve into a production line.  Please check with Perfecdos whether your PLC is suitable.

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What interchangeable spare parts are there for the valve ?

For the valve almost all of the fluid projecting parts are available as spare parts.

The Perfecdos dispensing valve is designed to be low maintenance and easy to maintain, therefore there is only a small range of spare parts necessary to maintain the valves optimal performance.

Nozzles

Perfecdos offers a variety of micro dispensing nozzles. The nozzles can easily be changed by the operator. The following nozzles types are available from our product range:

  • Nozzle form: Needle nozzle
  • Nozzle diameter: From 150 to 400m (graded)
  • Nozzle material: Stainless Steel & Plastic

Due to the in-house production process of our nozzles, it is possible to manufacture specific nozzles for our customers to be made if so desired.

Fluid Body

The fluid housing is situated on the bottom end of the valves casing and is comprised of the fittings for the nozzle and the medium supply. Depending on the field of application, the fluid body can be made of either stainless steel or plastic. The Perfecdos fluid body housing is highly robust and is characterised by its long service life. For maintenance purposes, the fluid body is removable. In practice it proved to be helpful having spare fluid bodies, because in the case of speedy maintenance, the spares would be clean and ready to use immediately. Cleaning can also be rationalised as more fluid bodies can be cleaned at the same time.

O-Ring Seal

The actuator system of the valve is separated from the fluid delivery components by O-ring seals. The O-ring seal is found in the fluid body housing and is comprised of two singular O-ring seals. Every time the valve is serviced the two O-seal rings need to be replaced (1 at the driving end and 1 at the fluid end). The maintenance interval is conditional to the current application. Therefore, the regularity of maintenance comes down to the medium being dispensed and the daily dispensing cycles undertaken. The valve is shipped out with NBR O-ring seals as a standard feature. Depending on what the dispensing medium is, an appropriate material for the seal ring can be chosen. The Perfecdos product range offers the following materials: NBR, FKM (Viton) and FFKM (Kalrez/Chemraz). The applied sealing material must be chemically and mechanically resistant to the dispensed material.

Fluid Connectors

Depending on the application there are different fluid connectors for the Perfecdos micro dispensing valve at your disposal:

Cartridge Connector

The simplest method to supply the Perfecdos micro dispensing valve is by using a conventional cartridge for the dispensing technology. They are equipped with a LuerLock connector (coarse thread with internal sealing cone) and come in the following sizes:

  • 3 cm
  • 5 cm
  • 10 cm - Popular Size
  • 30 cm - Popular Size
  • 50 cm

Tube Connector

With a larger quantity of medium, a pressurised supply tank will normally be used. The respective medium will be fed to the valve through a tube. The necessary tube connectors for suitable plastic tubing are available in the following diameters:

  • 6mm OD / 4mm ID
  • 8mm OD / 6mm ID

For high pressure applications a hydraulic tube can be connected directly to the G1/8" internal thread using a suitable adaptor.

Valve Nozzle Cap Nut

The cap nut secures the nozzle to the fluid body housing.

There are 2 different types of cap nut relative to the valve configuration:

  • Cap Nut Standard (10mm spanner size)
  • Cap Nut with Needle Protection (10mm spanner size)

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What has to be observed during maintenance ?

What Maintenance Work Can Be Performed By The Operator ?

All Perfecdos micro dispensing valves are designed for a long lifespan and low levels of maintenance. Through this, the parts of the valve which come in to contact with the medium can be maintained by the operator. All maintenance should be performed in accordance with the manufacturers guide. For details please refer to the operator manual supplied with the valve.

Maintenance Intervals

The maintenance intervals are directly related to the operating conditions, therefore the frequency of maintenance depends on the medium and the number of cycles completed daily (medium, continuous operation, number of shots and frequency of shots). In the early phases it is advisable to service the valve more regularly. After gaining some experience with the valve, the time between maintenance intervals can be prolonged. Condition and wear or soiling of the spare parts are factors which should be considered when determining the maintenance intervals. Poor or infrequent maintenance can lead to the premature malfunction of the valve.

Maintenance Procedure

Every time maintenance is performed all the electrical and pressure supplies should either be removed or deactivated to rule out hazards at work. All maintenance work should be performed in a clean area.

Changing The Nozzle

  • Remove the nozzle by unscrewing the cap nut (10mm spanner required)
  • Clean the valve 
  • Finally re-attach the nozzle with cap nut

Replacing The Cartridge

  • Disconnect the air pressure supply from the cartridge lid
  • Unscrew the cartridge from the fluidic housing
  • Beware of the remnants of the medium leaking out
  • Attach the fresh cartridge

Cleaning The Fluid Body

  • Remove medium supply source (cartridge/tube) from the fluid body assembly
  • If fitted, remove the heater assembly
  • Remove the fluid body housing by loosening & removing the 4 screws attaching it to the valve
  • Before reassembly the two O-rings on the tappet must be replaced with new O-rings
  • Apply barrier grease to O-rings before reassembly
  • Reassemble in reverse order

Cleaning Recommendations

When cleaning the valve, the aforementioned parts must be washed with an appropriate cleaning fluid (solvent). The 61025 Cleaning Kit from Perfecdos has been designed to help with cleaning the valve. All parts which come in to contact with the medium can easily be cleaned quickly with the use of an ultrasonic bath.

Attention: Protect you eyes and hands while cleaning.

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Do you have an application for Micro Dispensing - if so, please complete our on-line enquiry form by clicking here