![]() Originally I had the tables in flash memory but because flash memory is very tight, I moved them to the static RAM (Data space). ![]() A temperature of zero will be considered the end of the heat curve and any other slots ignored. The time is the number of seconds from the start to when that temperature should be reached. A plot is a series of six pairs of temperature and time values. The software can hold any number of heat curves. ![]() The software makes use of the attached thermistor library by Miguel Angel Califa Urquiza. The assembly process regardless of version remains the same. Note: some of the images are from by V2 build which used a mechanical relay. In STOPPED mode, it will start the displayed heat curve from the beginning. START: When in RUNNING mode, it will pause the at the current temperature in the heat curve and maintain that temperature until the START button is pressed again. In PAUSED mode, it will abandon the current heat curve. SELECT: When in STOPPED mode, it will select the heat curve to use. So now I have it on continuously when the temperature of the plate is more than 10 degrees over the ambient temperature. My previous design had the fan only switch on when it needed to cool the plate but its impact on the cooling the hot plate is limited. By using a solid state relay, PWM can be used to control the power to the heating element. My previous version used a mechanical relay but I found that the element at full power heated way too quickly and overshot the desired value by 20 degrees or more. ![]() The heating element is controlled using a solid state relay. The design of the electronics are based around a ATtiny1614 microprocessor and a 1.8in TFT SPI display. Join "SHP - Text.stl" to "SHP - Front.stl" using double-sided tape. The first 3 layers of "SHP - Text.stl" is printed using the front base color and switches to a contrasting color at the start of layer 4. The top, front, text and back pieces will need rotating on the built plate before slicing. The rest of the case follows a clam shell design.Īll printing is done using a 0.2mm layer height with no supports. Too fast a cool down period can cause extra stress on the component resulting in internal damage. After that the component is allowed to cool slowly. The melting temperature only lasts for around 20 seconds maximum otherwise there is a risk of damaging the component. After around 90 seconds at the soak temperature (usually around 150☌), the temperature is raised to the melting temperature of the solder (usually around 240☌). SMD components need to be heated firstly to a soak temperature to allow any water vapour to escape and also to allow the flux in the solder to activate. One of the down-sides of SMD components is when they are heated too quickly, water vapour that may have penetrated the component over time, may turn into steam and damage it. In the assembly of printed circuit boards, pick-and-place machines replace the older insertion machines. More and more designs incorporate or solely use surface mount components (SMD) rather than the more bulky through hole components. Over the years, electronic components have changed both in terms of size and also their footprint.
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