SCH launch a NEW NON-SELECTIVE inline spray system for uniform conformal coating film application for medium and high volume coating processing
NON-SELECTIVE inline spray system for uniform conformal coating film application
Conformal coating atomised spray application using a spray gun is an excellent method for applying coatings to printed circuit boards.
However, the problem can be that depending on the coating used, the circuit board to be coated and the thickness tolerance demanded, it can be difficult to get repeatable results.
Dr Lee Hitchens, Technical Director of SCH Technologies discusses the issues
“We are regularly asked for conformal coating equipment that can apply an even, repeatable coating film on a PCB using a spray application. This can be done with a spray booth but the operator needs to be very well-trained and disciplined. Also, if a tight tolerance of coating thickness is required, this can be pretty difficult for even the best operators. ”
“Another option could be to use selective robotic spray technology. However, the nature of the valve technologies does not easily allow variation in coating thickness as an option. In fact, most of the time the coating thickness is bound by the material properties, the robot technology and environment in which the machine is placed. Couple this with the cost of a typical selective coating system and it quickly becomes unattractive!”
Dr Hitchens explains further
“What we really wanted was a simple system that combined the repeatability of the XYZ platform, had easy programming, could provide the spray gun film forming quality and could do all this at a sensible price. So, we started to search for a solution.”
This search quickly found there was no perfect answer until SCH began work with TE Connectivity. They were developing exactly what SCH were looking to find a customer project.
However, using an atomised spray nozzle with a programmable XYZ system allows repeatable atomised spray results with fixed distances, patterns and speeds. This non-selective approach applies an even film of conformal coating over circuit boards without significant operator expertise and gives control to the film thickness without operator interpretation found in manual spraying.
Contact SCH Technologies for further information on inline spray system by ringing +44 1226 249019 or email us at sales@schservices.com
SCH Technologies are exhibiting in Bangalore at Electronica India in September 2014
Conformal Coating Equipment demonstrated at the show
SCH Technologies will be exhibiting at STAND 3125 at the Electronica Show in Bangalore from 23-25th September.
As part of our display we will be show casing
- Conformal coating Automated Optical Inspection Systems. SCH Technologies are working as a partner with German company, Modus, to provide an Automated Conformal Coating Inspection System for automatic inspection of conformal coatings and defect detection.
- Conformal coatings and masking materials such as tapes, dots and masking boots.
- Conformal coating equipment including our NEW LAUNCH conformal coating batch equipment especially for the Indian Market.
Come and visit us in September and talk to us about your conformal coating needs or contact us here at +44 1226 249019 or email sales@schservices.com
I have conformally coated my circuit boards and they are wet. What should I do with them now?
Ideally, the wet printed circuit boards (PCBs) should be allowed to dry in a dust free environment. Also, if they are solvent based coatings or have a hazardous outgassing then they should be extracted too. For this a cabinet would be ideal to store the PCBs in.
The DC100 floor standing drying cabinet was designed specifically for practical conformal coating allowing air temperature drying of conformal coating on the printed circuit boards (PCBs) away from air borne contamination.
The DC100 drying cabinet is designed to be used in conjunction with conformal coating application equipment. This compactly designed system not only offers an enclosed extraction area for protecting newly coated PCBs from contamination during the drying process, but also safely removing excess solvents through the attached exhaust.
Click conformal coating drying cabinets for further information.
Or, contact us here at +44 1226 249019 or email sales@schservices.com
Questions to ask when considering a Conformal Coating Dipping Application
When selecting a conformal coating process it is important to ask the right questions.
With dip coating, the information required includes questions such as:
- What is the size of the Printed Circuit Board (PCB) you wish to coat?
- What is the typical volume of the PCBs you want to coat per day, week, month etc?
- Is there any masking required on the PCBs?
- Do you know how you would like to hold the PCBs or do you need help with fixture design etc?
- Is the PCB to be dipped vertically, horizontally or at another angle?
- What is the material you wish to use for coating the PCB?
- Is the material compatible with a dip coating process?
- Do you require a batch process (operator loads and unloads at same point) or an inline process (load one end and take off at another station)?
- Do you require any curing mechanism within the machine (heat cure, UV light)?
- Do you require any automated control processes such as viscosity material maintenance and automatic material top up?
Asking these questions ensures that a dip coating machine supplier can provide a detailed quotation on the exact machine you need for your project.
Dipping PCBs in conformal coating
Dip coating is the simplest and highest volume conformal coating process to be used. If printed circuit boards are designed for dip coating the huge savings in money, time and effort can be made. For help on design rules for dipping contact us direct.
For further information on Conformal Coating Dip Coating CLICK
- Conformal Coating Dip Systems (Inline)
- Conformal Coating Dip Systems (Batch)
- Conformal Coating Dip Systems (Bench)
- Conformal Coating Dip Systems FAQs
Or, contact us here at +44 1226 249019 or email sales@schservices.com
SCH launch a full range of UV Cure products to compliment their UV Cure conveyors
As part of their continued growth into the conformal coating market SCH have introduced a new range of batch UV cure products. UV cure is fast becoming an important part of the conformal coating industry and to ensure that SCH meet the needs of the customers they have introduced several new products including:
These UV light products sit easily alongside the UV cure conveyors SCH has designed and manufactured offering state of the art UV cure products.
Contact us now directly or check out the links to see what we offer.
Designing for Selective Robotic Conformal Coating Processing: Rule 13 “Sticking coatings to non stick silicones is a pain”
Applying silicone RTVs to circuit boards to provide support to components for long term reliability is fine. Just don’t do it before you apply a conformal coating to the surface unless the conformal coating itself is a silicone. Acrylic and urethane coatings do not stick to silicone. So, don’t try unless you want defects appearing.
Rule 13
If you call out silicone staking materials for ruggedisation purposes, use a silicone conformal coating. If you don’t want to use a silicone conformal coating, then use a urethane or epoxy staking compound.
The Rules
The Rules for Selective Conformal Coating are straightforward. Follow them and you can save money and time in your application process. However, if the Rules are not followed, the resultant circuit board design can challenge even the most sophisticated conformal coating system and its operator to achieve the finish desired.
Click Designing Circuit Boards for Selective Robotic Conformal Coating for further Rules.
What is a needle dispense valve on a conformal coating selective robotic system?
This style of valve can be used to dispense more or less any material, from a no-flow gel to a water-thin consistency and the length of the needle used can help to ensure access between very tall components for example.
Dispensing from a conformal coating selective robot
To find out more about this and other valves for conformal coating application click Choosing the Right Valve for a Selective Robotic Conformal Coating Application Process
What is a contactless dipensing valve and how does it work with my selective robotic conformal coating system?
As the name implies, these valves typically operate between 2-10mm from the surface onto which they are dispensing and can apply very small dots or well defined lines and can be used to coat critical areas or discrete components. These types of valves generally work best with materials with some degree of thixotropy and medium apparent viscosities. These valves do rely on unhindered access to the coating area and are most suitable for SMT technology.
Contactless dispensing from a conformal coating robot
To find out more about this and other valves for conformal coating application click Choosing the Right Valve for a Selective Robotic Conformal Coating Application Process
How are the filters supplied for the conformal coating spray booth?
Each set of filters comprises of two filters, one for left and one for the right side of the conformal coating booth. They are identical shape. The top filters are green in colour and are for rough filtering. The bottom filters are white in colour and are for fine filtering.
There are 4 x set of green and 1 x set of white filters in each pack. This keeps it simple for ordering (one type of pack only!).
For usage of conformal coating spraying typically change green filters once/week approx, change white filters once/month (one pack per month).
Click Conformal Coating Spray Equipment FAQs to find out more about this and other issues relating to the process.
Why are there so many different conformal coating application methods?
Coating a printed circuit board initially seems to be a straightforward process. After all how difficult can it be to apply a “varnish” to a pcb? The problem is there are so many variables to consider.
First, there is the PCB itself. you must consider its size, the components on the PCB and whether they need to be coated or must not have coating on them, what you are protecting from (moisture, water, chemicals, heat etc) and the volume to be processed?
Once these details are understood then you have to select a conformal coating material. But, selecting a coating influences the application process. For example, choosing a UV cure coating obviously means a UV cure conveyor is required. But, it also means certain robotic valves cannot function in general with these materials. So, coating selection automatically influences the application method.
In fact, the material, the PCB and the application method must be considered as a whole to give you the best chance of developing the optimum process for costs, time and protection.
Click Which conformal coating application method should I choose? Do I dip, spray or brush? to find out more.
Conformal Coating 