Comprehensive Guide to SMT Machines: What are they and how to choose?

Nowadays, people's lives are inseparable from electronic products. As the brain of electronic products, the demand for printed circuit boards has also increased accordingly. Therefore, PCB manufacturers try their best to increase production, and one of the effective ways is to introduce advanced SMT machines on the production line. Using these machines, even tiny electronic components can be assembled quickly and with high precision.

In this article, we will introduce different types of SMT machines and their functions, and provide some tips for choosing the right machine for your production line.

Different SMT machines used in PCB assembly process

According to the order of SMT PCB assembly process, we will list the equipment used one by one as follows：

Solder paste printing machine

The first machine used in SMT PCB assembly is a solder paste printing machine, which secures the PCB in place in an automatic solder paste printing machine, where a scraper applies the correct amount of solder paste to the pad. Subsequently, the blade scrapes the template and evenly distributes the solder paste in the designated area where the component will be pasted, while the rest of the area remains unchanged. Finally, the machine removes the template. If everything goes well, the solder paste should now be in place so that the components can be placed later.

Solder paste inspection (SPI) machine

After applying the solder paste to the board, the next important step is to check whether the solder paste has been printed correctly on the board. Poor solder paste printing is usually the cause of SMD welding problems, so this stage is crucial. This is where the SPI machine comes in. This kind of machine can use a camera to capture 3D images, and then evaluate the solder paste based on the volume, arrangement, and height of the solder paste. It can also identify inappropriate sizes and defects.

Placement machine

Reflow soldering machine

Although the welding process is very precise and cautious, there is always the possibility of flux and excess solder remaining on the PCB. This is where solvent cleaning equipment comes in handy. The purpose of this dedicated SMT machine is to eliminate the remaining flux and solder on the PCB during the welding process, so as to ensure that the PCB is thoroughly cleaned and prepared for the next stage of the manufacturing process.

Repair and testing equipment

PCB inspection equipment is a highly sophisticated SMT machine designed to inspect and repair printed circuit boards. The machine can not only identify any potential defects or failures on the circuit board, but also help repair and repair them. The thorough inspection of the PCB is guaranteed by its high-precision and accurate measurements, which can identify and solve any problems before the final product is delivered.

How to choose the best SMT machine?

Choosing the right SMT machine for your assembly line is not an easy task, you should consider the following factors before making a decision：

Component placement speed

The placement speed of SMT placement machine is the focus of the initial research on the purchase of placement machine. The placement speeds of these placement machines vary, so it is very important to choose one according to your production needs and budget. You can check them according to the IPC 9850 standard, which defines the mounting speed of their placement machines.

Mounting accuracy

Placement accuracy is another important aspect that should be considered. The higher the accuracy of the machine, the better the performance, so as to achieve high-quality output. The best SMT machine should have an accuracy of 0.0001 inches and a fine-pitch lead of 12mil to achieve the best accuracy.

Machine repeatability

When choosing an SMT machine, not only its accuracy, but also its ability to produce consistent results must be considered. This is called repeatability and is a key feature to look for, especially in machines that use programming software solutions to operate.

Part size

Another important factor to consider is the size of the part. For example, a pick-and-place machine should be able to handle parts with sizes 0402, 0201, and 01005. If the machine you choose meets your other requirements but does not support these sizes, you can purchase additional nozzles or feeders to produce circuit boards of these sizes.