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Compact heat source and process control

Compact heat source and process control

Compact heat source and process control

(OP)
jones21 (Mechanical) 4 Apr 08 9:03  
My goal is: "I am looking for process control".

Currently I am using a Master heat gun 120V, 60 hz. 14.5 amps.  Temp range 750/1000 deg F.  It is working ok, but does have some issues.  The first problem is the word "GUN".  It is made to be a hand held unit.  I am looking for something that can be mounted and be repeatable from one winder to the other, and still have some kind of control on it's position. The distance from C/L of spindle, is critical in producing a "controlled process".  My background is Machining, so I see the issues with mounting a hand held unit,accurately.

The second issue I see is varying temp at working area.  I am looking for some kind of feedback controller to keep constant temp at working area.  I have other applications for this type of controller, on other projects also.

Temp tolerance should be +/-5 deg F.

Just a added note the heat gun I am currently using, may list temps 750/1000 F.  But at our working area it is more around 450 F.  That temp is working for me, so the unit I am looking for may not have to reach 1000F.  It will just have to be compact enough to keep working area around 450F.

One more issue is there can not be debris coming out of the heat source.  I have experienced issues like this before(insulation and other components breaking down in heat source and being blown out, into working area).

So in a nut shell there it is.
 
 

RE: Compact heat source and process control

  You can make your own heater in a (grounded) stainless steel tube that won't have anything to blow out.

  Make it whatever wattage you need.  Perhaps 50% more than needed to allow a speedy heat up time.  Then you control your heater with an off-the-shelf PID controller.

  Sense the temperature of your work using an optical thermocouple.  This is a device that looks at what you point it at and outputs a common T/C signal.  This signal you provide to the PID controller to close the loop.

  That should do the job you describe.
 

Keith Cress
kcress - http://www.flaminsystems.com

RE: Compact heat source and process control

(OP)
TO reply you itsmoked, I really  appreciate your input!  But you are making the assumption I have the same background as you...  Your answers are very simple and to the point, but I may need a few more details to make it happen.  No offence intended! OK.  

You refer to a heater, what kind of coil or components are in the tube?  I can understand the concept, a heater coil in a tube hooked up to plant air, I assume.  But may still require more input.  

You refer to a "off-the-shelf PID controller."  (I viewed your link and it has some impressive products).  Would your company be the source where I can purchase a "PID"?  


I did not know the optical thermocouple has outputs...  I will have to check into that..

Thanks again, Jones
 

RE: Compact heat source and process control

Hello jones21.

Perhaps you'd be more comfortable getting a turn-key system:
http://www.farnam-custom.com/air_heaters/digitherm.html

Down side is it accurately controls the air temp being delivered, not the actual work piece you are machining.
It might work for you though.

Or get a torch from them and continue with my originally described scheme.
http://www.farnam-custom.com/air_heaters/heaTorch.html
http://www.farnam-custom.com/air_heaters/flowTorch200.html

A PID controller like these are what I was referring to:
http://www.factorymation.com/s.nl;jsessionid=ac112b321f4331248d6230fc4e54a71db0818403c862.e3eSc38TaNqNe34Pa38Ta38Qchn0?sc=2&category=2


The non-contact thermocouple sensors I was referring to were ones like:
http://www.omega.com/toc_asp/subsectionsc.asp?subsection=J09&book=Temperature

Only you could decide what makes the best sense or I would need more info than can be conveyed here.  Plus this is Eng-Tips not Eng-Free Engineering lol

Thanks for the site compliment too. I wouldn't be the best place to buy just one PID controller.  I do either custom ones, embedded ones, or whole engineered systems using them, but I don't just resell them.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Compact heat source and process control

(OP)
OK thanks...  Your concepts have sparked some thought.  I have chased the PID concept you have offered, ruled out the tube heater concept...  Thanks?


I guess I did not know I was over stepping my bounds, by asking my questions.  I thought that was the concept of the fourm, but not my place to say...  

I will not post any new threads, so as not to piss off the locals, so to speak.  

I just was looking for a recommendation, on a purchased system that was not 3 grand or more.  

It's quite funny how P---- you folk's are... First I got blasted for not giving enough detail.  Then when I give the whole story.  I get "Plus this is Eng-Tips not Eng-Free Engineering "  My first question was simple and to the point.  "I need a compact heat source" and the response was more detail, in a smart A-- way...

Thanks, I think??
Jones

RE: Compact heat source and process control

Whoa settle down man.  I beg your pardon..

What are you talking about? "blasted for not enough detail"?

I often blast people for a lack of information in their questions..  Especially when the lack of info borders on rude: "I have a motor what fuse should I use?"

I also have no idea about you or your technical abilities.  As someone who has done work for hundreds of different people I see all levels of ability.  Your response showed me some lack of knowledge in these areas.  I have gone far in hunting down this info for you.  I spent almost an hour on my responses.

If you noticed the sensor link, there is a whole page of choices each of which has many sub choices.  I cannot guess my way thru the many possibilities as to which would be right for you, I would be wrong.  Do you need air purge or not, etc?  If you can't select the best one either, then you need to get some help from someone who is able to take your needs and condense them to physical items and a functional system.

  My point was, that can't be done here in a forum thread.  This is "Eng-Tips".  I have given you a bunch of 'tips'.

Quote:

"Plus this is Eng-Tips not Eng-Free Engineering lol"

Is only a friendly reminder that you can't expect us to provide a design via an Eng-Tips thread.

Respectfully,

Keith Cress
kcress - http://www.flaminsystems.com

RE: Compact heat source and process control

(OP)
OK itsmoked, I will tell you right out of the gate.  I really appericate the links and information you have provided to me, even more so now that you have told me, the amount of time you have taken to supply me with information!  Thank you very much!  I will be applying what you have provided, to the project...

   I in no way want to have a dissagreement with any one!  I have been a casual reader of the fourm for a couple of years.  I enjoy the know age that is distributed here...  

My background is in Machining, I have been a  machinist for 25+ years CNC or manual, now I have moved into the design area for the last few.  I have needed a smaller, better heat source that can be controled...  We are a little slow now so to fill the time I thought I would try this..   

Now the reason for my thin skin on the response...

I had listed my first tread on this subject a early last week.  With in a few days I receved a what I percieved as a sarcastic response from some one on not having enough detail.  I had briefly listed some info on what I needed.
So then I spent the time to clairfy the process I am in need of.  After a few days of not getting any response, I figured I was in the wrong group.  So I copyied it into this fourm. Bam here we are.  

I felt like you thought you were wasting your time and I was asking for more info than I should have.  
I could have done with out the sarcasm and maybe took it more to heart than I should have, but still could have done with out it...

Like I said I really value your information and I was not looking for a full design, only a concept and a company, where I could have detailed conversations with and purchase the components from...  Now with your info I have done that and have a constant feeback system in the works....

Thanks, Jones

RE: Compact heat source and process control

No problem.  I understand your "lack of info" comment now.

When I started participating in forums I had to learn to have a thicker skin and not get defensive too quickly.  I think it is easier for some than others.  It is sort of like the usual "half full or half empty" cup question.  Some of us jump to the defense side much faster while others may go too late.

I have been burned in dealings with conversations in writing several times.  It is very easy to have a reader take comments in a seriously negative manner when that was not even the intent.  I now try to not take anything I read in a negative manner unless it is clearly, deliberately, obvious, that is the intent.

Anyway glad that's cleared up.

It could be far cheaper if you you could heat your fixture and directly monitor its temperature instead of the hot air method.  I don't know what your process is so I can't say.  When heating jigs/fixtures you can use cheap cartridge heaters and a cheap thermocouple instead of the contactless variety which are kind of pricey, but work well.  Jig/fixture heating would also remove another 'thing' from the machining area and greatly reduce heating of the local environment usually.  Just a thought.

Keith Cress
kcress - http://www.flaminsystems.com

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