benchtop ionizer Archives | All-Spec's Official Blog

Get Lean with 5S Workplace Principles


5S - Sort, Set in Order, Shine, Standardize and Sustain Recognized as one of the strategies associated with “Just in Time” manufacturing (Toyota Production System), the 5S system for workplace organization and standardization originated in Japan. The “5” relates to Read more

PCB Rework – Evolving Cleaning Methods


Smaller devices makes PCB rework harder. Today's manufacturers of printed circuit boards (PCBs) strive for quality and drive operation yields close to 99% and above – yet some boards will still fail functional tests when coming off the assembly line and Read more

Ten Labels to Solve Your Engineering Challenges


Put the right one on There’s a right label for every application and Brady has designed a handy cheat sheet to help you on your way. When choosing a label, you’ll want to ask yourself several questions – Will the Read more

Dry Air Static Control and Ionizers

Posted on by Barb N. in ESD News, Static Control Tips and Tricks Leave a comment

Dry air and ESD control

The specifications and devices being assembled determine the recommended humidity range for a manufacturing facility. When the air is dry, static control becomes much more challenging. Although ESD events may be reduced by increasing the humidity, unfortunately that same humidity may cause a reduction in the quality of moisture-sensitive devices because of corrosion, soldering defects and the popcorn effect.

Ionizer choices for reducing ESD

Although ionizers cannot replace grounding or shielding of ESD work surfaces, ionization can lessen ESD events in areas where dry air is normal.  Desco has number of ionization products available through All-Spec.

  1. Benchtop and overhead Ionizers – work surface ionizers create positively and negatively charged ions that are moved to the controlled area with fan-driven airflow.
  2. Point-of-use air ionizers – use compressed gas to combat electrostatic attraction neutralizing charges on particles causing contamination or visual defects on products.
  3. Laminar flow ionization bars – used with laminar flow hoods, controlled chambers and other contained applications.
  4. Room Ionization – reduces electrostatic discharge (ESD) and electrostatic attraction (ESA) in cleanroom environments.

For more information, consult the ESDA’s TR20.20-2008 RH information. Below find some of the significant statements about dry air and static electricity.

dry-air-popcorn-effectESD Handbook ESD TR20.20-2008 Section 2.3 Nature of Static Electricity:

  • Static electricity in the form of static cling and static shocks are more prevalent when the air is dry.
  • Heating interior air in the winter months dries out the already dry air in the higher latitudes.
  • Static charge accumulation is easier on dry materials since moisture on surfaces tends to allow charges to slowly dissipate or recombine.
  • Humidity control alone cannot provide static control since static charges are developed even at relative humidity levels of 90% and greater.
  • For most situations, 30 to 70% RH is considered the appropriate range.
  • Special areas, such as wafer fabrication, may require lower humidity control for processes that are affected by moisture (e.g., photoresist application).
  • Soldering is known to be affected by high relative humidity conditions (>70%).
  • Ionization is an important consideration in areas with low ambient humidity to aid in reducing charge accumulation levels and provide neutralization of charges after they are developed but before they can cause difficulties.

 

desco-point-of-use-air-ionizerESD Handbook ESD TR20.20-2008 Section 5.3.16 Humidity:

  • Humidity is beneficial in all ESD control program plans.
  • Contact and separation of dry materials generates greater electrostatic charges than moist materials because moisture provides conductivity that helps to dissipate charge.
  • ESD effects are most noticeable in the winter since heating systems reduce building environment moisture.
  • Geographic location (desert vs. coastland) is a major contributor to ambient conditions inside buildings.
  • Any circumstance that results in a low relative humidity will permit a greater accumulation of electrostatic charges.
  • Relative humidity above 30% in ESD protective areas is desirable as long as other adverse conditions are not created as a result of humidity levels.
  • In general, an upper limit of 70% is desirable to prevent corrosive effects on the metal portions of electronic devices and assemblies.
  • Dry air increases the tendency to generate electrostatic charges on dry materials and performance of many ESD protective materials degrade.
  • When exposed to low humidity conditions, some ESD protective materials become totally ineffective or become sources of electrostatic charges.
  • Evaluation of ESD control materials should include performance testing in controlled environments at the lowest expected operating relative humidity level.
  • Manufacturers of ESD protective materials should be able to provide performance data in regards to relative humidity.
  • Materials should be tested in moderate humidity conditions as well to ensure they do not become “too conductive” and present a potential safety hazard to personnel working with substantial voltages. See the Personnel Safety section of this handbook for further guidance in this area.

 

Humidity control alternatives

 Humidity control in factories or physically large areas or buildings can be difficult and expensive. In smaller rooms or areas, it may be possible to use portable humidifiers to raise the immediate area humidity. However, in many large facilities and factories the environmental systems need to include steam generation and monitoring equipment to control humidity. This type of equipment is expensive to install and purchase especially in pre-existing facilities. To reduce the total cost impact, companies should consider the need for humidification equipment when planning new facility construction.


How Do Ionizers Work?

Posted on by Andy in Technical Articles Leave a comment

Benchtop IonizerWhen looking for equipment to keep your workplace ESD-safe you may come across air ionizers. Typically ionizers are used to ground insulated materials, as they cannot be grounded by attaching a cord like conductive or static-dissipative objects. In order to use ionizers correctly it helps to understand exactly how they work; so today we will be going over some basics of ionization.

What Do Ionizers Do?

The function of an air ionizer is to provide a way to neutralize a charge on an insulated object. This is achieved by using a device to create positive and negative ions, and then distributing these ions across the insulated object.

Air ionizers include a way to create ions (both positive and negative molecules) and a way to distribute those ions (usually through the use of a fan). When the ions blow over your workspace the negative ones will attract to any positive charges and the positive ones will attract to any negative charges. Once they bind to the charges your insulated object will be neutralized.

How Do Ionizers Make Ions?

There are three main ways that ionizers make ions. The two that are used the least in normal production are nuclear and photon ionizations. Typical work areas will not use these types, as nuclear ionizers use radioactive materials and are subject to government regulations, and photon ionizers use x-rays and are regulated by the FDA. The most common type of ionizer for normal production facilities are corona ionizers.

Corona ionizers create ions by applying a high voltage to the very tip of a sharp point. This creates a high electrostatic field, which interacts with electrons in the gasses around it. The electrostatic field then attracts and repels various electrons, creating ions in the gas molecules around it. The electrostatic field can then move the ions over the work area, but often corona ionizers also have a fan to make them spread further and more evenly.

How Do I Use an Ionizer?

The best bet to make sure you use your ionizer correctly is to consult the user manual or manufacturer. However, there are a few things to keep in mind for most ionizers to make them work to their full potential.

  • Make sure that your ionizer is able to cover your work area. Check that the coverage area is large enough, as any area outside of that coverage will not be reliably neutralized.
  • Ensure there is no interference from other fans or vents. If you have a cross breeze then that may affect the coverage area, or make your ionizer less effective.
  • If the ionizer has a fan, make sure the environment is right for your worker. If your workplace tends to be cold then you can get ionizers with built in heaters to help operator comfort and increase productivity.
  • Check the decay time of the ionizer for extra sensitive parts. If you need charges to be neutralized in a certain amount of time then you can find ionizers with low decay times.

Do you have any more questions on ionizers? Leave a comment below, or visit our site for information and specifications on different types of ionizers!