Our Capabilities

Supporting New Product Launches Nation-wide

PCB Assembly Capabilities

Printed Circuit Board Assembly (PCBA), also known as CCA or PWB, is the process of mounting electronic components onto a bare PCB to create a functional board. At BESTProto, we support all major assembly types, including:

Electromechanical Assembly Capabilities

We deliver speed, flexibility, and accuracy for any project, whether you need a simple sub-assembly or a complex system integration. Our core capabilities include:

Electronic Box Build Assembly Capabilities

BESTProto offers a variety of flexible options for integrating your electronic or electromechanical product into an enclosure.

Rack-Mounted Electronics Assembly Capabilities

BESTProto offers a variety of flexible options for integrating your electronic or electromechanical product into a rack-mounted enclosure.

Wire and Cable Harness Assembly Capabilities

We handle wire and cable installation projects of all complexities:

Lead-free Soldering Process Capabilities

BESTProto is your lead-free prototype assembly partner, with the processes, necessary equipment, and trained and experienced personnel in place. We have been working with the engineering development community for several years on the refinement of lead-free processes and assembly techniques. BESTProto has the engineering, processes, and capabilities to make your transition go smoothly.

Successful assembly methods have been developed by BESTProto for “lead-free” solders for all types of components. BESTProto has developed manufacturing techniques for the most common lead-free solders, including Sn/Ag/Cu and Sn/Ag alloys. The soldering manufacturing parameters are adjusted to accommodate the higher melting temperature and slower wetting characteristics of the “lead-free” solders. We have also developed practices for inspecting lead-free PCB assemblies.

After confirming that the parts and materials to be used in the lead-free assembly are available, suitable for the process, BESTProto focuses its attention on paste handling, printing, reflow, wave soldering, inspection, rework & repair, and cleaning to ensure that the quality of lead-free assembly is maintained.

Paste Handling Shelf Lives

“Lead-free” solder pastes whose storage conditions tend to be slightly more stringent than their tin/lead counterparts may be reduced when compared with tin/lead alloys. For example, BESTproto process technicians allow the paste to come to room temperature before use, and they do not mix old and new paste in the same jar. You can be assured that BESTproto follows proper paste handling procedures, which helps maintain consistent quality products that we build.

SMD Printing

There are no major equipment or process condition changes with respect to paste printing of lead free alloys. In general, no major changes to the printing process are necessary. Stencil life, aperture release, print definition, high-speed print capabilities, print repeatability, remain relatively unchanged.

However, “lead free” solder alloys have poorer wetting characteristics compared to tin/lead alloys, requiring some stencil design modifications to maximize paste spread and counteract inferior wetting.

Reflow

This is the SMT process area that is the most affected by a switch to lead-free assembly. Most “lead-free” alloys require higher reflow temperatures than the 210-220ºC peak temperature of tin/lead. An increase to the 235-260ºC temperature range is common. In terms of the reflow profile, making sure that the critical areas of the actual board are profiled based on the solder paste manufacturers’ recommendations and BESTProto process engineering experiences is the key to achieving repeatable results.

Lead-Free SMT Assembly

One aspect of “lead-free” solder alloys we have noticed impacting SMT assembly is the poorer wettability characteristics and ensuing smaller spread compared to tin/lead pastes. In addition, surface-mount devices tend not to self-align as well during reflow. As a consequence, the placement accuracy of the BESTProto hand assembly or our pick and place machine has proven invaluable.

Lead-Free Through-Hole Assembly

It isn’t practical to run both tin/lead and “lead-free” processes with a single selective wave soldering machine. We have a selective solder system dedicated to “lead-free” solders as well as one dedicated to the legacy tin/lead processes.

Wave Soldering

This is one area of the PCB assembly process where “lead-free” solders have major differences when compared to their tin/lead counterparts. Depending upon the alloy selected, “lead-free” wave soldering will require a pot temperature of 260-275°C. This increase in temperature and the change in solder alloy require additional process changes. Correctly formulated fluxes for the lead-free solder alloy are used to overcome the poor wetting of the “lead-free” alloys and higher thermal stresses of the wave process.

BESTProto has adopted the use of separate selective wave soldering systems for use in lead-free processing, as the increased caustic nature of the high tin content solders, as well as the higher processing temperatures, is maintained.

Inspection

There are a number of visual differences between tin/lead and “lead-free” solder joints. The latest version of the IPC-A-610D has been updated to account for the changes in the visible appearance of the solder joints. BESTProto inspects the assemblies to these new IPC-A-610D inspection criteria.

Rework and Repair

Operators have been trained for “lead-free” rework, as the lead-free solders do not flow as well as their tin/lead counterparts. One change is in the higher flux content in wire-cored solders. As with any change of flux chemistry. BESTProto technicians pay close attention to the operating conditions in the new operating window.

All rework performed uses the same lead-free solder alloy as originally used on the solder joint; different lead-free solder formulations are not mixed on the same solder joint. If more than one alloy is in use in production (i.e., Sn/Ag/Cu for SMT and Sn/Cu for wave soldering), operators are trained to use the correct solder wire for each part. For this reason alone, it is advisable to use a single solder alloy for all assembly operations. BESTProto uses a single standard SAC305 alloy for both reflow and selective wave soldering processes for this reason.

As part of our assembly process controls, work orders have a visual color coding as an indication (red=lead, green=” lead-free”) of the alloy that is to be used on a given assembly. Materials, including both flux and solder, are released per job order based on the alloy specified by the customer.

Frequently Asked Questions

About Our Capabilities
Does BESTProto support lead-free soldering?
Yes. BESTProto has developed manufacturing techniques for the most common lead-free solders, including Sn/Ag/Cu and Sn/Ag alloys, with processes, equipment, and trained personnel in place specifically for lead-free assembly.
Most lead-free alloys require a peak reflow temperature in the 235-260\u00b0C range, compared to 210-220\u00b0C for tin/lead solder.
Depending on the alloy, lead-free wave soldering requires a pot temperature of 260-275\u00b0C, along with correctly formulated fluxes to overcome the poorer wetting of lead-free alloys.
Yes. We use a single standard SAC305 alloy for both reflow and selective wave soldering, since mixing lead-free formulations on the same joint isn’t advisable.
Operators are specifically trained for lead-free rework because lead-free solder doesn’t flow as well as tin/lead. Work orders use color coding (red for lead, green for lead-free) to indicate the correct alloy for a given assembly.
Yes. Lead-free solder joints look visually different, so BESTProto inspects assemblies against the updated IPC-A-610D criteria that account for those differences.