PID Controlled Hot Plate
DIY Reflow Hot Plate
I've been working with SMD soldering for quite a while, however all my experience has been with a soldering iron, microscope and solder wick. An alternate approach that is gaining ground for the 'amateur' is using a hotplate. Some people use cheap kitchen hotplates from Target and convert them. However, I'd like to have a go at making something more substantial. After some searching on the web, I came across Keith's electronics blog.
Photo of Keith's Hotplate
Inspiration for this project was obtained from Keith's Electronics Blog. After seeing his approach, I realized that I would have to make one myself. My friend Scott also wanted one so we decided to make two at the same time and hopefully prevent each other from making mistakes. Link to Keith's excellent website and his post: http://www.neufeld.newton.ks.us/electronics/?p=537
Research & Planning
Most of the research and planning had already been done for me thanks to Keith and others before him. I decided on a similar design, however instead of the delicate ceramic standoffs, I came up with an alternate (untested) approach. I plan to use aluminium 'C' shaped pieces as feet however between them and the heating block and base would be a layer of insulating material.
The insulating material I'm going to be using is called Glastherm HT. It's rated up to a maximum 550 degrees Fahrenheit which should be fine for this project.
Machining the Parts
Heater Plate & Supports
Being new to machining, this was great fun for me. Starting off with a huge slab of Aluminium (or Aluminum now that I'm in the US!) and cutting it on the band saw by hand was scary and fun.
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- The Machining Jig.
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- All set up and ready to go!
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- First Pass Done!
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- Second pass in progress
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- Shiny.
Here's a quick video showing one of the machining passes.
Insulating Material
The heating plate and the struts are sandwiched on either side of an insulating material. This will hopefully prevent most of the heat from conducting down the support legs to the base. Cutting the insulator (Glastherm HT) was simply a case of cutting it to size on the band saw and then cleaning up the edges on the mill.
Electronics / Assembly
Information about the assembly process
Conclusion
Cool conclusion
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April 7th, 2010 - 13:10
Ben, beautiful work! The shots of the aluminum legs are very nice — they remind me of “modern” architecture when I was a kid in Iowa. I love the Glastherm, too. Now I understand why Scott cut me a piece of that before turning my new idler wheel, too.
Is the Glastherm brittle? I’m wondering about using *it* for legs — cut two 1″-wide strips of it, stand them on edge, and attach them to the heating block using L brackets (or channel). I may have to beg Scott to throw a couple of strips into my package for upgrading *my* hotplate!
April 7th, 2010 - 13:23
Thanks Keith! the Glasthem isn’t THAT brittle. It would probably suffice as some legs. It’s not very nice to machine though as it creates an incredibly fine dust that gets everywhere.
I’m well aware that the design is pretty over engineered, but I kinda got carried away with using the milling machine.
What’s you’re advice with regards to the heating element? Do you have a link to the one you bought?