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Headway Research, Inc.
Headway Research, Inc.

Frequently Asked Questions

1. What is the largest substrate that can be spun using a 10,000 rpm motor?
The PS, 10000 rpm motor, was designed to spin silicon wafers. However, throughout the years, we have learned that it can spin other substrates as well. Typically we do not recommend spinning substrates larger than 4" X 4" X .125" on this motor.

2. What are the advantages of using a recess chuck versus a mechanical locating finger chuck when spinning square or rectangular substrates?
The non-vacuum, recess and the carrier recess chucks are designed for the end user who needs to have uniform coatings all the way to the edge of the substrate. These chucks have a recess pocket that is machined, at HRI's machine shop, to the particular substrate dimensions and tolerances. Typically when using a recess chuck with our Inhibited Drying Spin Coating Kit, a better than 2% uniformity within a border of approximately .062" from all the edges has been achieved. The mechanical locating finger chucks are designed to help center substrates. These chucks have four adjustable finger extensions to accommodate various substrate sizes. This chuck is recommended whenever protection of the backside of the substrates is not required by the end user. Uniform coatings can be achieved when using our Inhibited Drying Spin Coating Kit, however, turbulence at the finger extensions may have some affect on coatings.

3. Are HRI spinners table top models?
Certainly. Our spinners can be supplied with portable stands for mounting on a table top or customers can easily mount them into hoods, benches or anywhere there is sufficient room. Please refer to our Mounting Options page for pictures and detailed information.

4. Can I spin very large/heavy substrates and small/light weight substrates using one machine?
It may be possible to spin substrates of varying sizes and weights using only one spinner. We recommend that you contact us to discuss your particular application. We have two motor models: PS and BD, each designed to spin substrates of varying dimensions and weights.

5. Why does the vacuum chuck need to be slightly smaller than the substrates? Can the chuck and substrate be the same size?
The chuck should always be slightly smaller than the substrate to avoid damage to the motor assembly as well as to prevent vacuum interlock problems. Substrates are held onto the chuck using vacuum (this does not apply to the non-vacuum, recess chuck line). If your substrate is smaller than the chuck a couple things may happen - 1) Material will surely get underneath the substrate which may,in time, reach the vacuum center hole. Once material reaches the vacuum center hole it will be pulled down into the motor assembly. Although several precautions and guards are in place to protect the motor, the possibility exists that over a period of time the material will reach inside the motor causing it to fail. 2) The substrate may not be large enough to seal the vacuum. The vacuum chucks are designed with a cross design to aid in vacuum distribution. If the substrate is not large enough to cover the entire chuck, vacuum may escape thus not satisfying the vacuum interlock and rendering the spinner inoperable. The chuck and substrate can be the same size but keep in mind that material may get underneath the substrate.

6. Can the spinner vacuum requirement of 23" hg be decreased in the field?
Yes. Although we do not recommend using less than 23" hg, we realize that instances will occur when you may wish to adjust your vacuum. Please contact HRI Technical Services for instructions.

7. Do you still support your older EC101/PM101 Spinners?
Definitely. Our goal has always been to design our spinner motors and motor packages with common, non-special components. Many of the replaceable components used on our EC101/PM101 spinner motor packages are used in our current spinner line. We stock most parts for all our spinner models, even our 1960s models.



The model PWM32 Spin Controller has been upgraded and new product is now called model PWM50. We buy used equipment and factory re-furbish it at times, so the PWM32 may linger in our terminology and sales material for a considerable time. References to the PWM32 will be updated as soon as practical.

See the special page explaining the main differences in the two models.

8. Can your spinners be nitrogen purged?
Yes. We began supplying a nitrogen purge on our spinners in the early 1990s with our EC101DT Spinner Series. Our newer PWM32, PWM202, MP100 Spinner Series also have nitrogen purge as a standard spinner feature.

9. What can I do when my spinner is buzzing and the Vacuum Error appears on the LCD screen?
This is one of the safety features that has been a part of our spinners for over 30 years. You do not have enough vacuum to satisfy the vacuum interlock system. Although you may have vacuum at the chuck it may not be enough to allow the spinner to begin operation. Here are some preliminary checks . a) You must first find out if you have enough vacuum coming from the vacuum pump or vacuum source. b) You need to use a gauge to check the amount of vacuum being generated. We recommend you have at least 23" hg for good spinner operation. c) Check your vacuum connections to make sure that they are tight. On the PWM32 Spinner Series check the vacuum source to controller connection and the controller to motor package connection. On the EC101/PM101 Spinner Series check the vacuum source to the motor package connection. d) If you have enough vacuum and you notice that the vacuum is weak at the chuck, you may have a vacuum leak. e) Check the vacuum chuck to make sure that the 1/4" bottom chuck o-ring is in good condition. f) If your chuck has an o-ring on the chuck surface, check to make sure this o-ring is in good condition. g) If you have a flat surface type chuck check to make sure it is clean. Sometimes material can get onto the chuck surface causing vacuum to escape. h) Make sure that your substrate is seated properly and that it is larger than the chuck. As mentioned earlier, these are preliminary checks. If you have any questions or need further assistance, please contact HRI Technical Services.

10. Is it possible to change bowl sizes if I need to later?
Yes. We have designed our spinners so that the customer can easily change their spinner's bowl size as substrates increase or decrease in size. Our conversion kits can change your bowl to either 7.9" (R790) or 15"(CB15).

11. Do your spinners have a lid?
For many, many years we have provided spinners without lids. We are very safety conscious and have designed our spinners to ensure that the operator is protected to the best of our ability. We have been asked to provide lids and have in the past with our Inhibited Drying Spin Coating Kit for reasons other than safety. The reason for our hesitation is that we do not know how this will affect air flow and thus coatings inside the spinner bowl. We have ongoing projects to address this in the future, but at this time we do not have enough data to add this feature to our spinner line.

12. After activating a programmed recipe, the controller give me a "secinterlock" waiting message and then, after about 14 seconds, there is a loud beep and a "vacuum problem" message appears. Do I have a vacuum leak? If so, how can I tell where?
Try the following steps:

  1. Take the vaccuum chuck off and put your finger over the motor shaft.
  2. Try to run the motor.
  3. If the motor runs, the chuck is where the vacuum is leaking. Check the chuck o-ring to make sure it is in good condition.
  4. If the motor does NOT run, then disconnect the vacuum hose on the bottom of the motor.
  5. Plug it with your finger and try to spin the motor again.
  6. If the motor runs, the vacuum leak is at the hose connection. Check to make sure that the hose is connected properly.
  7. If the motor does NOT run, disconnect the vacuum pump and try to spin the motor.
  8. If the spinner runs when the vacuum is off, the vacuum switch is being bypassed.

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Headway Research, Inc.
3713 Forest Lane
Garland, Texas 75042 U.S.A.

Phone (972) 272-5431
Fax (972) 272-7817