Frequently Asked Questions (FAQ)
Plasma Product Questions
What size are Harrick Plasma Cleaners’ chambers?
|Basic Plasma Cleaner||Expanded Plasma Cleaner||High Power Expanded Plasma Cleaner|
|Chamber Size||75mm diameter x 170mm length||150mm diameter x 170mm length||150mm diameter x 170mm length|
What are Harrick Plasma Cleaners’ power settings?
Basic Plasma Cleaner
Expanded Plasma Cleaner
High Power Expanded Plasma Cleaner
High RF power
What are Harrick Plasma Cleaners’ operation frequency?
Our plasma cleaners operate at MHz frequency. This has been found to be beneficial for many applications, in comparison to plasma cleaners that operate in the kHz range.
Do you provide onsite support or training?
We do not provide on-site installation or training. However, you can easily set up the plasma system on your own and most of our customers have performed the installation without any problems. You will require a few tools (hand wrenches, screwdrivers) to attach vacuum connections and valves.
Detailed installation and operation instructions are also described in the user manual, which is included with the shipment. We can readily provide more technical assistance by phone, email, or video chat if needed. Our response time is quick, typically within 1-2 business day.
In addition, here is a link to a video showing Plasma Cleaner Installation.
Can I add a gas cylinder?
IMPORTANT! Make sure that pressure regulator, gas tubing, fittings, and tubing adapters are chemically compatible with the gases being used.
If you plan to use a gas cylinder source, you will need to provide the following from your gas supplier:
1. Gas cylinder and gas-compatible pressure regulator capable of delivering pressures of 10 psig (70 kPa). We recommend a two-stage regulator, which is able to deliver more stable, consistent output pressure. We also recommend that the pressure regulator includes a shut-off valve at the regulator output.
2. Adapter at pressure regulator output to connect the gas-compatible tubing.
3. Gas-compatible tubing to connect pressure regulator output to the metering valve input on the plasma cleaner front door or to the PlasmaFlo input (1/4″ Swagelok fittings). Both metering valve and PlasmaFlo output have ¼” Swagelok (compression) fittings and we provide a 1/4″ outer diameter (OD) hose adapter to connect to the ¼” Swagelok fitting. Some options for tubing:
- Option 1: Use the provided 1/4″ OD hose adapter to connect 1/4″ inner diameter (ID) flexible tubing. Use hose clamps to seal each end of flexible tubing.
- Option 2: Remove the ¼” OD hose adaptor and use 1/4″ Swagelok nut and ferrule set (compression fitting) to connect 1/4″ OD rigid tubing.
Is a vacuum pump required?
Yes, the minimum required items to run the plasma process are a plasma cleaner and a gas-compatible vacuum pump (minimum pump speed of at least 23 L/min and ultimate pressure of 200 mTorr or less). All three of our vacuum pumps include the accessories needed to connect the plasma chamber to the pump inlet (3 ft. vacuum hose, hose clamps, pump inlet adapter, seals, and clamps).
Does my pump meet your minimum specifications?
The vacuum pump must have a minimum pump speed of at least 23 L/min, and an ultimate pressure of 200 mTorr or less. Usually, a rotary vane pump or dry scroll pump would meet these requirements and a diaphragm pump would not.
The vacuum pump must be compatible with the process gases used in the plasma cleaner. Consult with your pump supplier on whether your vacuum pump is compatible with the process gases.
You will also need to provide your own accessories (vacuum hose, hose adapter, seals) to connect the plasma chamber to the pump inlet. The plasma chamber narrows down to a 1/2″ outer diameter tube in the back of the chamber. We recommend using a vacuum-rated 1/2″ inner diameter flexible hose and hose clamps on either ends to seal the connection.
We also recommend attaching an exhaust hose to your pump outlet to conduct the pump exhaust away from the lab space and to a vent hood or fume hood.
How is your plasma cleaner operated?
Harrick Plasma cleaners are manually operated, with no automation. The plasma treatment process is simple and easy to set up and learn. While process conditions (gas, power, time) are application specific, the plasma treatment process can be summarized as:
- Turning on the plasma cleaner
- Inserting Samples
- Targeting Vacuum Pressure
- Switching on RF Power and timing plasma treatment
- Venting and power off
What is the maximum operation time?
We recommend continuously operating for no longer than 2 hours at a time. Following the completion of the plasma process, the main power should be turned off to further prevent overheating.
What temperature is plasma?
The plasma itself is essentially at room temperature. The chamber temperature can increase because of heating of electrical components inside the unit during operation. A cooling fan runs during operation to mitigate the heating.
For dielectric, non-conductive materials such as polymers or ceramics, the sample surface is also roughly at room temperature during plasma processing.
Conductive materials can be heated during the plasma process through inductive heating (coupling with the RF field), where the surface temperature of a conductive material may increase by ~5 degrees C with 5 minutes of plasma treatment The temperature increase is slight, but does increase with power and treatment time.
Why isn’t plasma forming in my plasma cleaner?
If you are having trouble with plasma formation, these issues are usually caused by either a problem with the electrical circuit or vacuum pressure where the chamber is not within the proper pressure range (below 1,500 mTorr, though we recommend operating from 200-800mTorr) for plasma to be generated and sustained. We recommend running the fluorescent bulb test to determine if you are experiencing an issue with the electrical circuit: Video of Fluorescent Bulb Test
Why isn’t my vacuum pressure as low as expected?
Check the vacuum connections listed below. Note that all national pipe thread (NPT) tapered fittings (these would be on the 3-way valve) should be wrapped with Teflon tape and wrench tight. Any time NPT fittings are disconnected, all the residual teflon tape should be completely removed from both internal and external threads and fresh tape should be applied when reconnecting the fitting. Wrap tape clockwise when threads are facing you (at most 2 wraps around the threads is sufficient). Applying excessive Teflon tape can also cause poor vacuum seal.
Connection between plasma chamber outlet and vacuum hose. Make sure to use a hex nut driver and NOT just a flat-blade screwdriver to further tighten the hose clamps at the vacuum hose ends; This is the most common location of vacuum leak.
- Connection between vacuum hose and straight shaft of pump inlet (make sure hose clamp is tight)
- Check chamber for cracks or defects; check chamber lip for particulates or defects.
- Check o-ring on front door or particulates or defects
- Connection between valve assembly and plasma cleaner front door. Be sure the valve assembly is threaded into the door by hand until you feel resistance (3-4 turns) for a good vacuum seal.
How do I check my plasma cleaner fuses?
Check that the plasma cleaner fuse is functional. Turn off Main Power and unplug the power cord. You should see a fuse holder (with white rectangular face plate) next to the plasma cleaner power cord. Remove the spring-loaded fuse holder and remove the 2 fuses.
Inspect the fuse for a thin filament that is intact from one end to the other. If it cannot be determined visually, use an ohmmeter or multimeter to measure electrical resistance across the fuse contacts. It should be < 1 ohm. If the resistance shows “OL” or “overload”, the fuse is blown and should be replaced.
Check your user manual for fuse replacement information specific to your model.