Posted by
Brad Welch on Thu, Feb 16, 2012 @ 09:10 AM
The classic use of the Buy vs. Make analysis in the context of impregnation involves deciding whether it is better to send parts to an impregnation service center or to install impregnation equipment in your own facility. Depending on the circumstances, each approach to sealing castings has merit.
While outsource cost, freight and value held in WIP are obvious considerations for the BUY option, ensuring part quality remains the most important criteria for a program. Typically, a decision to outsource would be made when a program requires impregnation of low volume, low value parts for obvious reasons.
A capital expenditure would be difficult to support in such a case, and the nature of the part makes it an easy part to be run in service center equipment that is designed to handle a variety of materials, part sizes, etc. As volumes and part value / complexity grow, an outsource solution may still make sense if the service center has available capacity which is capable of ensuring that the parts can be processed without damage and without risk of residual sealant contamination. Qualifying the supplier in this context is very important.
The Make option is dependent on many variables but annual spend and program longevity are the main considerations. The range of the spend is not set in stone as equipment costs vary significantly between used and new, batch and continuous flow. The program longevity should be at least three years. Make costs to be assessed include:
- Equipment cost
- Floor space
- Modifications of plant infrastructure and existing layouts
- Operating costs, all of which can be, and should be, controlled by the equipment design
- Electric
- Water
- Sealant consumption
- Effluent regulations
- Availability of qualified labor and maintenance resources
- Reliability of approved sealant sources
- Internal cost of funds and payback period requirements
- Whether the process fits in the organization’s strategy and structure (i.e. is it to be regarded as a core competency)
There are certainly many examples of high volume high value programs that are handled by qualified impregnation service centers without quality issues. With that said, equipment technology has advanced to the point where it is feasible to bring impregnation in-house in an operation that requires full automation with minimal operator interface. The decision can only be made with a simultaneous assessment of both process quality and cost considerations.
If you have additional questions to help you make a decision on whether to outsource or buy equipment, please contact us.
This year’s EUROGUSS attracted a record number of domestic and foreign visitors to Nuremberg as 8,200 people were looking for information about die casting foundries and foundry suppliers. The 383 exhibitors, of which 42% were international companies, did not just make contacts – many took orders. A wide range of products were represented from die castings, materials, furnaces, die casting machines and moulds to after treatment, quality control and research and development.
Godfrey & Wing GmbH received many visitors at their booth who were eager to learn about the newest innovations in vacuum impregnation. GW showcased its Continuous Flow Impregnation (CFi) technology. This technology makes it possible to integrate the impregnation process directly into a lean production environment, realizing sealing rates of over 98% and resulting in dramatically reduced impregnation per unit costs.
The philosophy and realization of the pure process and the perfect control of the process was well received. The visitors understood the advantages of the dry vacuum and pressure (DVP) process. Visitors also expressed a strong interest in learning more about the CFi through in-house technical presentations and workshops.
Thank you to everyone who visited the Godfrey & Wing booth. We look forward to working together.
Technology, Processes & Products
The 9th EUROGUSS trade fair takes place January 17-19 in the Exhibition Center in Nuremberg. About 400 exhibitors are expected to provide information on the latest technology, processes and products. Over 7,000 die casting experts from Germany and abroad will use EUROGUSS to prepare for investments due at the beginning of the year and look for solutions to their technical requirements.
Godfrey & Wing, the worldwide authority in vacuum impregnation, will showcase their patented Continuous Flow Impregnation (CFi) technology and equipment. Godfrey & Wing will exhibit in Hall 7A, Booth 108.
The CFi technology now makes it possible to integrate vacuum impregnation directly into a lean production environment. Costs like transport and WIP can be reduced or completely eliminated. This CFi technology is providing tangible benefits for major OEMs in the United States, and recently Godfrey & Wing introduced this technology to the European Vacuum Impregnation market.
See this revolutionary technology for yourself at EUROGUSS 2012. We are looking forward to your visit.
Why does GW recommend the dry vacuum and pressure (DVP) process?
Actually we don’t recommend any one process over another. What we do recommend is that customers evaluate the processes upstream and downstream of the vacuum impregnation system and ask questions like:
- Will the product be delivered to the impregnation system with the same quality day in and day out?
- Are any processes subject to inherent variation due to temperature, plant or atmospheric conditions that could impact the quality of the product?
- How many parts do I need to get in and out of the process?
- Will it be directly connected to my process flow or be located offline?
- Do I anticipate the need to impregnate all parts or only ones that fail test?
- Will I be impregnating different parts from different suppliers with different geometries and different alloys?
- What kind of test specification must the product meet?
In our service facilities we ask these questions every time we install a new or refurbished system. For our internal use the answers lead us to DVP. Our service centers process components from thousands of customers with a wide variety of metal castings, plastics, cables, and even rocks! Therefore we have to impregnate parent materials with a wide range of porosity and voids, from fine micro-porosity in magnesium and aluminum to some open porosity in cast iron to the long voids found in stranded cable. And to top it off we need to do this quickly to deliver a sealed component to a customer cost effectively. Time is money. Therefore DVP is our service center system of choice.
Well surely since GW uses DVP in their service facilities it must mean DVP is the best for all customers, right? Nope.
Let’s look at pressed or powdered metals. A cost effective wet vacuum system works very well for these parts as it is all “through” porosity. Some high density PM materials actually benefit from a wet vacuum pressure process. Insert molded connectors may often be sealed with only a wet vacuum process.
Then there are cases where a customer will impregnate one part number in low volumes. Given a stable casting process, a dry vacuum process could work well and may be proven by running samples prior to purchasing a system.
So while we don’t promote one type of process over another our service centers chose the DVP process so they are equipped to handle a variety of sealing demands, from the easiest to the most difficult.
One thing is for sure, the day your capacity runs short or your parts don’t seal because all the questions were not answered thoroughly is a sad day indeed.
If you are considering purchasing a vacuum impregnation system, you may be interested in our Vacuum Impregnation Equipment questionnaire. You can complete the questionnaire here, and then we will put together a customized plan to help you achieve your goals.
Posted by
Tom Shantz on Thu, Dec 29, 2011 @ 10:40 AM
In order to help determine what size vacuum impregnation system you need, there are a few questions you should answer first. The goal is to determine the total volumes and size of the parts that need to be impregnated and how that fits into your existing manufacturing schedule.
What are the properties of the parts that you want to impregnate? We need to determine the total envelope size in square inches.
- How many different part numbers are there?
- What is their size?
- What is their weight?
- Are they made of aluminum, iron or zinc?
- What is their machined state? (raw, partial or full)
What is your manufacturing schedule?
- How many hours per day?
- How many days per week?
- How many days per year?
Once you have answered these questions, click here to download the Godfrey & Wing basket utilization tool which will help you determine the total number of parts estimated to be contained in the basket.
Posted by
Tom Shantz on Thu, Dec 08, 2011 @ 10:50 AM
At Godfrey & Wing, we are often asked how large and how small of a pore may be sealed or how long it takes to fill porosity using vacuum impregnation. There are multiple variables that directly impact this answer including the relationship between sealant viscosity, pore size and pore depth.
We know that impregnation sealants flow easily through small pores since Godfrey & Wing sealants are routinely pumped through a 1 micron filter during the filling of containers.
The variables that impact flow and penetration of sealant into porosity are:
- Size of pore to be filled
- Depth of pore to be filled
- Viscosity at application temperature
- Percent of air removed from the pore
- Pressure applied to force sealant into pore
Flow calculations are based on the experiments of early 19th century French physician Poiseuille. Poiseuille observed that flow is proportional to the radius of the cylindrical tube raised to the 4th power. He also noticed that it is inversely proportional to the length of the tube and the liquid viscosity. This formulation was published in 1846 and is known as Poiseuille’s Law (PL).
Some considerations must be taken into account when applying PL such as porosity is not perfectly cylindrical, and the size of the porosity varies throughout the component. For more detailed information about the relationship between sealant viscosity, pore size and pore depth and Poiseuille’s Law, click here to download the complete whitepaper.