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SMD Reflow Hot Plate: New Version is a March 6, 2023 DIY project by John Bradnam, not a newly released commercial appliance. It upgrades his earlier 200 W plate with a 400 W, 220 V heater, an approximately 140 × 70 mm heating area, two 70 mm cooling fans, an ATtiny3224-based controller, TFT display and programmable temperature curves. It is a promising tool for experienced makers assembling small prototype boards, but it is not certified, automatically safe or validated for production reflow.
Verdict in brief
The design is worth considering if you can fabricate a PCB and enclosure, program a tinyAVR microcontroller and work competently around 220/240 VAC. Its larger plate and active cooling address the main limitations of the earlier build. However, the published project provides no temperature-uniformity map, thermocouple logs, repeatability results or independent solder-joint validation. Treat its three firmware curves as starting points, then measure the actual PCB temperature with a thermocouple and tune the process to your solder-paste datasheet.
Project files, schematics, firmware and assembly information are available on the Hackster project page.
What this project is
This is a temperature-controlled hot plate that heats solder paste and surface-mount components from below. The enclosure, controller PCB, firmware, 3D-printed parts and mounting structure are intended to be built by the user. It is open hardware in the practical maker sense, not a ready-to-buy product.
#1 Best Overall
- Three-dimensional cooling hole design: multi-angle cooling design for better cooling effect and strong practicability.
- High quality aluminum plate as the heater 30-400 ° C: multi-tube technology efficient heating tube ensures good heat transfer effect
- This item can be used to divide, repair cell phone screen, LED display, Component work, SMD reengineering work, PCB removing, soldering work
- Welding and maintenance of aluminum substrate in LED industry; Preheating of mold core in abrasive factory; Constant temperature heating for sealing, dispensing in electronic industry ; Baking, drying and other temperature test of constant temperature heating samples in various industries; Essential tools for laboratory, analysis room and teaching research
- The constant temperature heating platform adopts high-performance CPU to control temperature, it has accurate temperature control and strong practicability
The plate is useful for small, mostly single-sided prototype boards. It is not equivalent to a convection or vapor-phase reflow system: heating is primarily through the board underside, thermal contact can vary, and a single sensor cannot prove that every component has followed the same profile.
What changed from the 200 W design?
| Area | Earlier design | New version |
|---|---|---|
| Heater | Approximately 200 W | 400 W, 220 V |
| Reported heating area | Smaller plate | Approximately 140 × 70 mm; the author describes this as roughly double the earlier area |
| Cooling | Less effective single-fan arrangement | Two 70 × 70 mm fans below the plate |
| Controller | Earlier ATtiny device | ATtiny3224 named in the project description |
| Power arrangement | Earlier low-voltage arrangement | 240 VAC-to-12 VDC module, 5 V regulator and solid-state relay |
| Ambient sensor | Present | Removed |
| Cooldown threshold | Earlier implementation | Software threshold of 45 °C |
The extra heater power is a design change intended to heat a larger plate; the project does not publish comparative heat-up measurements. Likewise, the author reports that the two fans cool noticeably better, but gives no measured cooldown time.
Why the temperature profile matters
Reflow is not simply “heat until the solder melts.” A controlled ramp gives flux time to activate and allows moisture to leave boards and moisture-sensitive components before the high-temperature phase. A long soak around 150 °C can be useful, but it is not universal.
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1Clear out junk files and repair common Windows errors2Scan for outdated or missing drivers - takes under a minute3Repair Windows errors before they cause bigger problemsRank #2
- This compact soldering hot plate comes with built-in temperature control (PID Program/Cycles in milliseconds), with adjustable temperature range from 122°F~752°F; Supports soldering or rework applications on SMD components such as LED diodes, BGA chips, and more without concern on overheating
- The reflow hotplate is made from quality aluminum with 3.94x1.97inches (100x50mm) effective heating area, the heating plate is protected with metallic guards
- Can be used in conjunction with hot air rework station or soldering station to remove BGA chips by applying heat from the top and bottom
- Features °C - °F conversion function, and a digital read-out for easy real-time temperature reference
- Commonly used for SMD components soldering, phone screen preheat, glue removal, and other heating applications
Use the solder-paste manufacturer’s profile for the exact alloy and formulation. Kester’s published guidance, for example, specifies different ramp, soak, peak and time-above-liquidus requirements for leaded Sn63/Pb37 and lead-free SAC products (NXG1 data; standard leaded profile). Component moisture-sensitivity instructions also apply. A programmed plate temperature is not the same thing as the temperature at a component lead.
Firmware curves
The firmware contains three selectable plots. Each has six temperature/time slots. A zero temperature ends the profile, and the later slots are ignored. The period is elapsed time from the beginning of the profile to that target, not the duration of that individual stage.
plot1 = {
{150, 90}, {150, 180}, {240, 240},
{240, 260}, {0, 420}, {0, 0}
};
plot2 = {
{150, 50}, {180, 140}, {240, 175},
{240, 185}, {120, 250}, {0, 350}
};
plot3 = {
{150, 60}, {200, 120}, {250, 160},
{250, 190}, {0, 260}, {0, 0}
};These are starting recipes, not validated production profiles. In particular, a 250 °C target may damage some components, plastics, finishes or solder pastes. Measure the board and compare the resulting ramp, soak, peak and time above liquidus with the paste datasheet.
Rank #3
- High Efficiency Heating & Durable Aluminum Alloy Plate: Constructed with a premium aluminum alloy heating plate for high thermal efficiency, fast heat transfer and uniform temperature distribution. A full heat insulation wrap design prevents accidental burns for safer operation, with an adjustable temperature range of 30–400℃ to meet diverse heating needs.
- Multi-Tube Heating Technology & Standard Plate Size: Adopts high-efficiency multi-tube heating technology paired with a high-quality aluminum heating plate for faster, more even heat transfer; the heating plate measures 200×200mm/7.87×7.87inch, a universal size for most soldering and preheating tasks.
- 3-Side Cooling Holes & Low-Noise Operation: Features a 3-side heat dissipation design for enhanced ventilation and heat dissipation efficiency. No fan is required for operation, ensuring ultra-low noise during use and stable performance for long-hour work.
- Microcomputer Precise Temperature Control: Equipped with a microcomputer CPU-controlled temperature panel for accurate constant temperature heating, rapid temperature rise and uniform heat distribution. The temperature can be precisely adjusted to your specific operational requirements for consistent results.
- Versatile Professional Applications: This hot plate station is ideal for cell phone screen separation and repair, LED display component processing, SMD rework and PCB desoldering and soldering. It is also an essential piece of equipment for laboratories, analysis rooms and teaching & research institutions
Controls and normal operation
- SELECT: In
STOPPED, choose a heating curve. InPAUSED, abandon the current curve. - START: In
STOPPED, start the displayed curve. InRUNNING, pause at the current temperature; press START again to continue.
Before loading a board, check that the thermistor is firmly attached to the underside center of the plate, the board lies flat, and no screw head or case edge lifts it. Test the display, buttons, fans and temperature reading first. Never leave the heater unattended. The 45 °C stop/cooldown threshold is a software condition, not proof that every metal part, enclosure area or board is safe to touch.
Hardware and bill of materials
Thermal and control parts
- 400 W, 220 V hot plate
- 100 kΩ NTC 3950 thermistor
- ATtiny3224 microcontroller
- 1.8-inch color TFT display
- 5 V, 240 VAC, 2 A solid-state relay
- Two 70 × 70 mm case fans
Power and electronics
- 240 VAC-to-12 VDC, 450 mA power module
- 1117-5.0 regulator and BC817 transistors
- Tactile switches, LEDs, buzzer, connectors, headers and SMD passives
Mechanical parts and tools
- 3D-printed clamshell case parts
- FR4/copper-clad mounting material
- High-temperature insulation and Kapton tape
- UPDI/jtag2updi-style programmer, soldering tools, multimeter and temperature logger or thermocouple
Mechanical construction
The heater passes through an opening in the top half of the clamshell. The fans sit underneath and force air around the plate during cooldown. Countersunk mounting holes prevent screw heads from lifting a larger PCB. The thermistor was initially placed in the heater-element hole; testing led the author to relocate it to the plate’s center underside with Kapton tape.
- Assemble and inspect the controller PCB.
- Install the display, switches, LEDs, buzzer, relay, regulator and connectors.
- Fit the 12 V power module and its protective cage.
- Build the fan and hot-plate mounting structure.
- Attach the thermistor to the plate underside.
- Fit the assembly into the printed case.
- Wire the fans in parallel. Insulate each unused tachometer wire separately; do not tie them together.
- Complete heater, mains socket, switch and power-module wiring.
- Program the MCU, then perform electrical and thermal checks before a real board.
Mains wiring is the major safety issue
The enclosure contains 240 VAC. A low-voltage microcontroller does not make the appliance intrinsically safe. Use a mains-rated inlet, switch, cable and SSR; provide appropriate fusing, strain relief, insulation, conductor spacing and protective earthing or a properly engineered double-insulated enclosure. Keep mains and logic wiring physically separated and retain the cover over the power module. Inspect with power disconnected, verify continuity and insulation, and have a qualified person review the work if you are not experienced with mains construction. Provide ventilation for solder fumes and keep combustible material away from the exposed hot plate.
Rank #4
- High quality aluminum plate as the heater 30-400 ° C: multi-tube technology efficient heating tube ensures good heat transfer effect
- Two-dimensional cooling hole design: multi-angle cooling design for better cooling effect and strong practicability.
- This item can be used to divide, repair cell phone screen, LED display, Component work, SMD reengineering work, PCB removing, soldering work
- Welding and maintenance of aluminum substrate in LED industry; Preheating of mold core in abrasive factory; Constant temperature heating for sealing, dispensing in electronic industry ; Baking, drying and other temperature test of constant temperature heating samples in various industries; Essential tools for laboratory, analysis room and teaching research
- The constant temperature heating platform adopts high-performance CPU to control temperature, it has accurate temperature control and strong practicability
Programming caveat: ATtiny3224 versus ATtiny1614
The narrative identifies an ATtiny3224, but embedded Arduino comments still mention an ATtiny1614, including board and pin-mapping information. Do not assume the published programming settings are verified for the 3224. Before flashing, confirm the exact fitted MCU, Arduino board definition and clock, UPDI wiring and programmer, every pin assignment, and library support. Check the Eagle files and current megaTinyCore documentation against the physical PCB.
How to validate a usable profile
- Read the paste datasheet and record its recommended ramp, soak, peak and time above liquidus.
- Attach a thermocouple to a representative PCB pad or component area, not only to the heater underside.
- Run an expendable board at the selected curve.
- Measure center and edge temperatures; a single plate can have substantial gradients, especially with copper-heavy or warped boards.
- Record overshoot, settling and cooldown. The earlier relay design reportedly overshot by about 20 °C; the new PID/SSR version has no published overshoot data.
- Inspect joints under magnification for wetting, voids, tombstoning and component movement.
Repeat calibration after changing board size, copper distribution, paste, thermistor mounting or fan arrangement. Moisture-sensitive parts must also be stored and baked according to their manufacturer’s instructions.
The Tool Desk
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Strengths
- Larger working area than the original build.
- Programmable curves and editable firmware.
- Active underside cooling.
- Open design that can be repaired or customized.
- Convenient access to a board during experimentation.
Limitations
- Exposed hot surface and mains voltage in a self-built case.
- No published thermal map, repeatability study or production validation.
- A single sensor may not represent PCB or component temperature.
- Uneven contact, board warping and edge-to-center gradients remain possible.
- Two-sided boards can disturb components during the second pass.
- Firmware documentation has the MCU mismatch described above.
Which alternative fits?
| Option | Best for | Trade-off |
|---|---|---|
| Miniware MHP30 | Small boards and localized rework; 30 × 30 mm, 60 W, USB-C, 100–350 °C | Far smaller than this project; SparkFun listed $189.95 during research |
| Miniware MHP50-B5 | Portable commercial plate with more capacity than MHP30; up to 100 W via 20 V USB-C PD or 150 W at 20–24 V DC | Still less working area and customization than the DIY design; verify live price |
| Hot-air station | Selective heating, rework and large or double-sided boards | Less convenient for heating many components at once |
| Reflow oven | Board-wide, repeatable profiles and larger or two-sided boards | More space, cost and thermal/electrical precautions |
| Professional assembly | Yield, inspection and documented repeatability | Less hands-on control and usually higher per-board cost at very low volume |
For boards larger than the practical area, Bradnam later documented a 500 W “jumbo” design with an approximately 200 × 100 mm surface (project page). Its larger enclosure and heater increase mechanical and mains-safety demands.
Best Value
- 【High Efficiency】 T55 preheating station equipped with aluminum radiator for high thermal efficiency. When using a 65W PD power supply under 25.2V, it only takes 87 seconds to heat from 30°C to 280°C. Working temp range: 50°C-280°C.
- 【Small but Powerful】 Mini & lightweight soldering hot plate with a heating area of 55 x 55mm. Adopts high-quality aluminum plate as a heating element, T55 transfers heat faster and more uniform.
- 【Multi-functions】 Preset temperature, time heating, automatic sleep, compensate temperature, multi-language menu, and firmware upgrade.
- 【More User-friendly】 The heater is equipped with an OLED display and two physical buttons(on the back), easily control & adjust temp. Slip-resistant silicone base to ensure stability.
- 【Wide Application】 This hot plate can be used on the workbench or out in the field, preheating & heating & desoldering circuit boards, components, LED beads, etc.
Who should build it?
Build this 400 W version if you value editable hardware, need more area than compact commercial plates provide, have 3D-printing and PCB access, and can calibrate the actual process safely. Choose a commercial plate for convenience and a packaged product; choose hot air for selective work; choose an oven or assembly service when board size, two-sided assembly, repeatability or yield matters more than experimentation.
Frequently Asked Questions
Is the SMD Reflow Hot Plate New Version a commercial product?
No. It is John Bradnam’s March 6, 2023 DIY Hackster project, with user-built electronics, enclosure, firmware and mains wiring.
Can I use the listed 240 °C or 250 °C targets for any solder paste?
No. Match the exact paste and alloy datasheet, then verify the board temperature with a thermocouple. The firmware targets are only starting points.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Is the ATtiny3224 firmware documented consistently?
Not completely. The project description names ATtiny3224, while code comments reference ATtiny1614. Verify the MCU, pin map, board package and UPDI setup before programming.
The Bottom Line
This is a capable maker project, not a certified reflow system. Its 400 W heater, approximately 140 × 70 mm plate and dual-fan cooling make it more practical than the earlier 200 W design, but safe construction and measured thermal validation remain the builder’s responsibility.
Quick Recap
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