DIY USB-PD Powered MCH Automatic Reflow Hotplate

Description

This is probably the first open source USB-PD powered MCH hotplate on the internet, even featuring the automatic reflow profile for Sn63Pb37 but not other specific solder paste design for low temperature reflowing.

The issue is that MCH hotplate is a bit tricky to get and finding one with specific specification always require custom made. This design factors in the difficult of souring such components and design the hotplate components to be swap-able with a PCB hotplate or MCH hotplate with different spec. Just change a few lines of code in the firmware to control the power switching frequency (and hence, adjusting the power to the hotplate), this PCB design basically fits most of the heating element you can find online with suitable sizes and power rating.

Details

Background Story

As an electronic maker, it is getting harder and harder for me to create new projects as parts (mostly IC and surrounding components) are getting smaller and smaller. About 10 years ago, SOP package IC are still easy to find which range from supporting USB2.0 or Serial communications. But in recently years, most ICs other than those require heat dissipation like battery charging or power management ICs, signal ICs are hard to find in SOP packages.

Design Goal

As I always to make something else other than power banks, I need to figure out a way to make soldering smaller packages IC less painful. The issues is that unlike makers from other country who usually have a larger space to work with, I live in cities with workspace smaller than a toilet in western countries. That is why I need to find a solution that is

Small, compact
DC powered (as I don't feel comfortable working with AC)
Fully automatic reflow like an infra-red reflow oven

I did try to look for some solution on the internet, the closest I can get is either a proper reflow oven or those tiny rework hotplate that uses PCB hot-plate, which do not met my requirement regarding my "dream reflow stations".

That is why I decided to make one myself. Though, this is one of my most expensive and hard to complete projects in recent year due to complexity in material sourcing. I will share with you in details in later steps.

What Make This Build Special?

The issue is that MCH hotplate is a bit tricky to get and finding one with specific specification always require custom made. This design factors in the difficult of souring such components and design the hotplate components to be swap-able with a PCB hotplate or MCH hotplate with different spec. Just change a few lines of code in the firmware to control the power switching frequency (and hence, adjusting the power to the hotplate), this PCB design basically fits most of the heating element you can find online with suitable sizes and power rating.

Files

firmware.zip

Arduino Firmware (for Ch552G)

x-zip-compressed - 4.44 kB - 01/06/2024 at 14:12

Download

Gerber_PCB_Reflow Hotplate v4.1.zip

x-zip-compressed - 178.66 kB - 01/06/2024 at 14:12

Download

wood_suppv3.ipt

MDF structure source file (require laser cutting)

ipt - 192.00 kB - 01/06/2024 at 14:12

Download

wood_suppv2.dxf

MDF structure (for laser cutter)

AutoCAD DXF - 467.36 kB - 01/06/2024 at 14:12

Download

base.stl

3D printed base

Standard Tesselated Geometry - 185.73 kB - 01/06/2024 at 14:11

Download

Components

1 × Metal Ceramic Heater 40 x 40mm (20V 50W)

1 × PCB Electronic Components / Misc. Electronic Components

1 × Temperature sensor 100k 1% thermistor

4 × M3 x 10 stands off

4 × M3 screw

Project Logs

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Introducing the v6 / v7 65W Reflow Hotplate!

tobychui • 07/21/2024 at 02:54 • 0 comments

After a few more revisions of the hotplate, I finally get this perfected!

The new v6 hotplates replaces the touch button for a physical buttons so it is more tactile when working with messy workspace. The major differences from the previous version is that

Support reflowing PCB larger than hotplate size
Much higher power (60 - 65W) with a new custom ordered MCH module
Added desolder mode, so you can rework damaged PCBs and extract components
Uses non-copper plated FR4 for support structure instead of MDF wrapped in Kapton tape and insulation layers
Updated the PD trigger IC to CH224K to support more modern PD power supply protocol
while keeping the cost identical as the old revision!

Build Instructions

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3D Print the Mounting Base

First you can start by 3D printing the base. It is a simple step. Just get the stl file, slice it and send it to a 3D printer.

Send the PCB to Print

As the PCB is the main component of this build, you can order your PCB at any PCB manufacturer you preferred. This project is sponsored by JLCPCB. If you have never tried to order a PCB before, please feel free to try out JLC services with the link below.

https://jlcpcb.com/

In my case, as the MOQ of the MCH hot-plate is 50 pcs, so I order a bunch of them from JLC so that I could make a few more of them and give them away with only the material costs.

You can find everything you need for the PCB over here on my github repo.

https://github.com/tobychui/MCH-PD-Automatic-Reflow-Hotplate/tree/main/pcbSide Note

I am using the v3 design but later I found that adding a small 0.1uF caps over the output of the L7805 improve the overall stability when using cheap / low quality GaN charger with large ripples. This is optional but I recommend adding it if you are making one for yourself.

Laser Cut the Hot-plate Support Structure

The hotplate support structure is a piece of 3mm MDF that is wrapped in Kapton tape. This prevent the MDF from smoking and turning black after long period of uses.

Discussions

Pete wrote 01/09/2024 at 22:11

Take my money! I want. :)

Are you sure? yes | no

Dan Maloney wrote 01/09/2024 at 00:33

Hi Toby, great looking build, so compact! Wrote this up for the blog, should publish soon. Great stuff!

Are you sure? yes | no

tobychui wrote 01/09/2024 at 01:11

Cool! Looking forward to the blog post :D

Are you sure? yes | no

DIY USB-PD Powered MCH Automatic Reflow Hotplate

Description

Details

Background Story

Design Goal

What Make This Build Special?