Our SMT line: accurate and fast production of printed circuit boards for electronics

29 April 2021

In this week's article, we tell you a bit more about our SMT production line. Since 2017, Rompa Group offers their clients the possibility to produce printed circuit boards for electronic devices (PCBAs). This in-house production is efficient and faster for electronic devices in general, but it also gives our customers a more comprehensive range for manufacturing these devices.

What is the SMT production line?

SMT stands for surface mount technology, PCB stands for printed circuit board. To mount electronic components directly onto the surface of a printed circuit board, we use the SMT production process. This means that we also give our clients the possibility to produce circuit boards (PBCAs) for electronic devices. Electronic manufacturing using SMT implies that the electronic components are assembled automatically. The SMT line machine and the SMT assembly line equipment place the electronic components onto the surface of a board.

Our SMT machines are mainly used for sectors such as telecom, automotive, strategic electronics and healthcare. Therefore we must be capable of placing components with a high level of accuracy, especially in modern times where technology is increasing in complexity and variety. Downsizing of the circuit boards also became an important innovation as the demand is for smaller and faster boards.

SMT-line process flow

Below a short description of the general process flow of SMT-line machines. The SMT-line cycle time can vary for different projects depending on the materials that are used.

1. The SMT-line process starts with preparation. We prepare and examine the SMC (Surface-mount components) and PCB whether any issues could arise during the process.

2. Preparation of the stencil that is used to provide a fixed position for the solder paste. The stencil is fabricated during the design process.

3. Next, we print solder paste onto PCB.

4. Then the solder volume and quality are inspected by SPI.

5. The electronic components are placed by the SMT pick and place machine.

6. Now the boards will be placed in the reflow soldering oven. The reflow soldering process contains several steps:

a. First, the boards will be preheated. The temperature rises gradually at this step.

b. Then they go into a soak zone where the boards are kept at temperatures from 140 to 160 degrees celsius for 60 to 90 seconds.

c. In the reflow zone, the temperature rises again by 1 to 2 degrees celsius per second and peaks at 210 to 230 degrees celsius. This will melt the mixture of the solder paste and bond the components together.

d. It's now time to cool down and ensure the solder mixture is set correctly.

7. Once the boards are cooled down after the reflow soldering process, they are ready for cleaning and inspection. First, the boards are cleaned, this gives an optimal view of whether there are any flaws, any repairs needed or other defects show. Inspection is done with the help of x-ray machines, ICT(In-circuit tester), AOI (automated optical inspection) and magnifying lenses.

SMT line efficiency

Line efficiency is essential for every manufacturer and assembler. This goes especially for printed circuit board production. Line efficiency is the ratio of the number of hours a pick-and-place machine positions parts on the PCB divided by the quantity of hours the SMT assembly lines are staffed. The overall aim is to manufacture as many PCBs without quality loss of the product in the shortest period of time.

Let's improve our efficiency!

We always continue to improve our line efficiency. Collecting data is one of the many important ways to improve efficiency. But just collecting data is not enough. With the data, we calculate and identify factors that could be improved.

What does our SMT line consist of?

A lot of innovative machinery is used with the production of printed circuit boards. SMT line equipment consists of various specially selected elements, below several machines that Rompa Group uses in the SMT line.

The laser marking machine gives us the possibility to accurately mark positions
SMT stencil printers
- The line always contains a solder paste screen-printer. The stencil printer applies the solder mixture with high accuracy.
SMT 3D SPI (Solder Paste Inspection) machine

3D inspection guarantees full inspection coverage with the most accurate measurement of height, area and volume of the paste deposits

Two SMT machines, also known as pick and place machines
- High speed and high precision of placing electronic components such as capacitors and resistors onto the printed circuit boards
Reflow oven
- As explained in step 5 in the SMT process flow, the oven needs several zones where temperatures can be individually controlled.
Curing machine
- Post-curing is essential for PCBs. During this process it allows the prints to achieve maximum hardness.
SMT assembly line equipment
- The assembly equipment consists of several modules with onboard control systems so they can function independently. At Rompa Group, we always aim for production efficiency, which in return reduces costs. The innovative assembly modules are a great step towards maximum efficiency.
AOI inspection equipment
- The automation optical inspection is fully automated, which eliminates human error.
X-ray inspection machine
- Inspect solder quality of the BGA components.
Curve PCB cutting machine
According to a pre-edited route dividing device, the curve cutting machine is a multi-use high speed milling contiguous PCB board. Replace the artificial break, V-CUT PUSH or cutting defects, and improve product quality, reduce scrap rate.
Wave soldering machine
- Especially for sodering DIP components.

Contact Rompa Group for more information

There is a lot more to tell about our SMT line, and we are always available to tell you all about it. Are you interested in learning more about the possibilities Rompa Group offers regarding the production of printed circuit boards for electronics? Do not hesitate and contact us! Did you know that we also offer many other technologies for manufacturing different objects? Make sure to check out all our technologies that we use at Rompa Group.

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