Mitch Holtzer

Mitch Holtzer has submitted responses to the following questions.

Oxidation of Solder Balls During Secondary Reflow
In general, proper cleaning would remove solder balls from the solder mask. Balls, like the solder joints created during the ...

Moisture Barrier Bag Calculation
We solved a very similar issue by immersing the irregular shaped sample in a measured volume water. The volume of ...

Moisture Barrier Bag Calculation
We solved a very similar issue by immersing the irregular shaped sample in a measured volume water. The volume of ...

Maximum Allowable Time Prior to Washing When Using Water Soluble Paste
Our requirement for time between a dual sided reflow and cleaning water soluble paste has been 48 hours since 2008. ...

Tented Via Options and Tradeoffs
Open vias can often create voids in the solder joint. During reflow, the gas in the open via expands, and ...

Cleaning No-Clean Solder Paste
Water soluble solder pastes are designed to be easily cleaned, leaving little or no measurable residue. No clean pastes are ...

Toe Fillet Requirements on Gull Wing Components
Toe fillets created a number of lively discussions in the past 2 decades of solder paste formulation development at Alpha. ...

Solder Contamination Sources
Dross management can alter the ratio of tin/silver in a lead free alloy, and the Tin/Lead ratio. Attempting to recycle ...

Point to Pint Soldering vs Drag Soldering
A wave soldering process may solve this issue. If you do not have a wave soldering machine, there should be ...

How To Measure Solder Paste Rolling Diameter
The diameter of the solder paste roll height is very important. Too much paste will cause sticking to the squeegee. ...

Insufficient Barrel Fill on Through-hole Components
The surface finish can have an effect if the assemblies were subjected to one or more prior SMT reflows. Immersion ...

Channels To Reduce Voids in Large Pads
Our research has shown that time above liquidus is inversely proportional to voiding area. In some cases, the use of ...

Using Solder Paste Beyond the Expiration Date
Good question. When solder paste ages beyond its useful life it it usually due to a viscosity increase that makes ...

Concerns With Silver Finish Component Leads
The silver will quickly alloy with the tin in the lead free alloy, but you will not have the same ...

Selective Solder System Purchased At Auction
Drain or ladle as much of the tin lead solder as you can from the machine. Fill it with chunks ...

Solder Splashing During Wave Soldering
From the information given, two potential causes need to be ruled out. If there is residual liquid flux (alcohol or ...

Solder Paste Mixing
Mixing solder paste in a centrifuge can cause flux and other ingredients to separate from powder particles and is not ...

Reusing recovered solder paste
It is not advisable to re-use solder paste once it is removed from the stencil. The paste can be stored ...

Dust contamination after selective soldering
Are you using a dross recycling system? Our testing shows that the alloy produced from an in house dross recovery ...

Mixed Process Solder Joint Appearance, Smooth or Grainy?
The ROHS compliant finish on your component leads is most likely tin. The relative amount of tin that becomes part ...

Environment Impact on Assembly, Printing and Reflow
If you have an open tray of paste or flux, used for a package on package application, particle build up ...

0201 Pick & Place Nozzle Plugging
It's quite possible that the .004" thick (100 micron) will have higher print transfer efficiency and leave as much or ...

Viscosity of Solder Paste Before Printing
Viscosity is a complicated issue with regards to solder paste. Solder paste is usually a shear thinning material, meaning the ...

QFN Test Failures Caused by Flux
The first question is whether or not the failure is a bridge between two adjacent I.O. s, or an open ...