What is a jet valve or jetter?

A jet valve is a valve for contactless media dispensing. The stream cuts off after closing the valve or a drop of dispensing media flies freely before it hits the substrate.

 

What are the advantages of “jetting” over contacting dispensing media?

No cut-off movement upwards, so there’s no z-axis motion

• Higher dispensing frequency and throughput rate
• Better z-axis tolerance lessens danger of substrate damage during dispensing
• Easier machine configuration
• Precise repeatability at small dispensing quantity without drip

 

 

What are low, medium and high viscous fluids and which systems are suitable?

 

• Low viscosity below 1 to ca. 300 mPas MDS 3010A
• Medium viscosity below 1 to ca. 8000 mPas MDS 3020A
• High viscosity above 300 mPas to 2 Mio mPas MDS 3200A

 

 

When to use a VERMES series “MDS 3000” jet valve?

Typical criteria for the use of VERMES micro dispensing valves:

• Small dispensing points and quantities between a few nanolitres and a few microlitres. This results in dispensing points on the surface from 0.2 to 0.3mm (minimum) up to a few mm, depending on fluid viscosity and surface properties of the substrate.
• High dispensing frequency, i.e. many dispensing points in a short time:
• A fixed installed or a continuously moving valve allows for frequencies of some hundred dispensing points per second
• In a system where the valve approaches each dispensing point individually, the dispensing frequency depends on the interaction between axes and valves as well as the distance between dispensing points. With correspondingly fast axes and short travelling distances more than 10 points per second are possible
• For more information concerning frequency and dispensing time which might even be relevant for system planning read the topic ‘integration of a MDS 3000 in an automated system’
• Concurrent higher repeatability precision requirements at small dispensing quantities
• Large work piece tolerances need to be compensated, so a z-axis critical needle dispensing is not practicable
• Parts in contact with media need to be cleaned and even disinfected easily

What do MDS, MDV, MDC und MDF stand for?

MDS: Micro Dispensing System
MDV: Micro Dispensing Valve
MDC: Micro Dispensing Controller

 

Which systems comprises the MDS 3000 series?

MDS 3010A-FD
MDS 3010A-FA
MDS 3020A-FD
MDS 3020A-FA
MDS 3200A

 

What do the suffixes –FD and –FA signify with the systems MDS 3010A and MDS 3020A?

FD = First Drop: Suitable for most low and medium viscosity applications. Adjustment (see "What's adjusting?") by precise screwing of the nozzle unit (NU). This process is electronically controlled.

 

FA = Fixed Adjust: Suitable for special applications/media and systems which make use of a large number of valves in a highly parallel way. Electronical adjusting without screwing.

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What's a nozzle insert, what's a nozzle unit?

NI or Nozzle Insert is the actual nozzle at the MDV. The nozzle insert is about 3 mm in diameter and is available in different hole diameters. Additionally, there are nozzle inserts with needles for low viscous fluids. Choosing the right NI usually depends on the dispensing fluid used.

A Nozzle Unit, NU, is the complete module attached to the MDV (valve body). Inside the NU there's the so called tappet guidance (TG). The NU integrates NI in TG; it’s available as “self-locking” and “not self-locking”.

 

What’s fluidic?

Fluidic is the part of the MDV where the fluid flows, in short MDF or Micro Dispensing Fluidic. The MDF is attached to the engine (valve body) with just two screws and can therefore be demounted quickly for cleaning or replacement.

There are different versions of the MDF, e.g. for inserting cartridges, pivoting, left or right offset, with tube connection or as UNF. Fluidics are available in different materials for different dispensing fluids.

 

How do I assemble a system for my dispensing needs?

The MDS 3000 series is modular. This allows for numerous configurations:

• • The first step is selecting the right system (MDS 3010A, MDS 3020A, MDS 3200A). This selection usually depends on the medium’s viscosity.
  • Choose the right nozzle inserts and the plunger where necessary. In most cases the desired size of dispensing points is crucial for this decision.
  • Chemical resilience may be important for the selection of parts in contact with the fluids like sealants and the Fluidic.
  • The fluidic profile depends on whether a cartridge or tubing connecting to a feeder tank is being used. More fluidic profiles are available for special inserts.
• Finally, even the cable length can be adjusted to system requirements

Why are there two cables per valve?

Due to crosstalk, the power harness needs to be separated from the signalling cables.

Actuator cable: supply voltage for the piezo element

Sensor cable: data transfer between MDV and MDC

 

What are the standard cable lengths?

2m, 2.5m and 5m, custom lengths are available.

 

Was versteht man unter einem Jetventil oder Jetter?

Ein Jetventil ist ein Ventil, das ein kontaktloses Dosieren der Medien erlaubt. Das bedeutet, dass der Strahl nach dem Schließen des Ventils von selbst abreißt, bzw. ein Tröpfchen des Dosiermediums frei fliegt, bevor es auf dem Substrat auftrifft.

 

What’s adjusting?

In order to dispense as precise as possible – regardless of plunger abrasion – the customer adjusts and readjusts the distance between nozzle insert and plunger on site. It is not necessary to send in the valve for adjustment, not even after replacing the nozzle insert and the plunger. Details on adjusting can be found in the manual.

 

What are RI, FA, OT, NL, DL and NP?

RI = Rising, the valve’s opening time in ms

FA = Falling, the valve’s closing time in ms

OT = Open Time: the period of time (in ms) in which the valve remains open

NL = Needle Lift: the percentage of maximum standardized plunger lift the system achieves at the respective setting

DL = Delay: idle time (in ms) between one completed dispensing cycle and the next

NP = Number of Pulses: Number of dispensing cycles initiated by one trigger impulse

 

What’s the difference between supply pressure and dispensing pressure?

Supply pressure pressing down on the dispensing medium in order to secure the material feed

The dispensing pressure that generates the dispensing jet is generated between plunger and nozzle insert and can’t be measured directly. Generally it’s significantly higher than the supply pressure.

 

Does the supply pressure affect the dispensing result?

With the other settings (RI, FA, OT, NL, DL) unchanged, it can be said that a higher supply pressure generally leads to a larger dispensing quantity. Varying supply pressure can lead to inaccurate dispensing results.

 

end faq