Pace Worldwide Nitrogen Assisted Soldering Information

PACE NITROGEN ASSISTED SOLDERING PRESS RELEASE

NITROGEN ASSISTED SOLDERING

Lead-free solders do not behave or look like their lead containing counterparts. As our industry changes over to lead-free solders, individual PCB assemblers will need to address several issues relating to hand soldering and rework. These issues include:

• Higher melting temperatures which mistakenly lead to operators increasing equipment operating temperatures. Higher operating temperatures do not make the process quicker, they actually slow it down.
• Poor wetting and spreading properties – Additional time is required when working with lead free solders, they do not spread or wet like lead containing solders do. Operators must slow down.
• Difficult to work with - Bridging and insufficient solder defects are common, even for experienced operators, leading to operator frustration.
• Dull grainy finish – makes inspection difficult.

Because lead free solders oxidize quickly, more aggressive and longer lasting fluxes are required to keep surfaces clean and free from oxidation. Working with no-clean fluxes is challenging as their process window is often small. Once they are gone, oxidation immediately begins to form which can result in a marginal or defective solder joint. Additionally, increasing operating temperatures creates an ideal environment for oxidation to form and will also lead to flux and solder ball splatter on the PCB. If the flux is splattered all over the PCB, it’s not able to do its job on the surfaces to be joined during the soldering process.

Lead Free solders also affects soldering and rework tools and their effect is detrimental. Lead free solders contain high percentages of tin, almost always over 94%. Tin is a corrosive and active metal. When it mixes with iron (the protective layer on soldering tips), an inter-metallic compound is formed that wears away more quickly than the iron would either by itself or when used with lead containing solder. This causes two problems, one is shorter tip life as the protective iron coating is dissolved in the tin, and the second is that oxidation forms more quickly which is further exacerbated by the high temperature environment the tips work in. As a result, tin oxides form and create an inter-metallic compound with the iron plating on the tip. Once the oxidation begins to form, the tip will lose its ability to wet with solder and if not cleaned off quickly, it becomes almost impossible to remove and the tip must be replaced.

The use of nitrogen assisted soldering equipment helps to mitigate the problems associated with using lead-free solders. Nitrogen helps on two fronts. First, it creates an inert environment around the soldering tip, reducing the potential for the tip to oxidize. Second, it assists in the soldering process at the PCB level by purging oxygen from the immediate area which reduces or eliminates the formation of oxidation from the work site. This not only reduces the amount of flux that is required, but it also helps to improve wetting, spreading, and leaves a finish that is shinier and less grainy.

N2 PASSING THROUGH HEATER

ST 45N 120 VAC Part Number: 8007-0346
ST 45N 230 VAC Part Number: 8007-0347

To use the N2 regulator accessory, an N2 source must be connected to it. Flow rates can be regulated between 1 and 10cfm. See chart below for system and handpiece compatability

	TD-100N, 4 Pin 6993-0273-P1 (kit) 6010-0155-P1 (handpiece only)	TD-100N, 8 Pin 6993-0273-P1 (kit) 6010-0155-P1 (handpiece only)	PS-90N, 4 Pin 6993-0275-P1 (kit) 6010-0116-P1 (handpiece only)	PS-90N, 8 Pin 6993-0274-P1 (kit) 6010-0157-P1 (handpiece only)	N2 Regulator Accessory required (6993-0271-P1)
HW 50
TW 50
MBT 350
ST 25
ST 45
ST 45N
ST 125
ST 145

PACE is also pleased to offer the NF 500 and NF 1000 nitrogen farms. Nitrogen farms harvest N2 from a compressed air supply that is passed through a specialized filter. The other atoms that make up “air” are forced through the filter, leaving a pure stream of N2 as the product of filtering. Nitrogen farms are passive collection devices which means that there are no electrical or moving parts, little or no maintenance, low running costs, and they maintain the balance of air/N2 in a confined space (as long as the compressed air is pulled from the same space).

FILTERING PROCESS

NITROGEN FARM FLOW SHEET