General Description of Blanchard Grinding
Blanchard grinding is also referred to as rotary surface grinding or vertical spindle grinding. Its value lies in the fact that it is the fastest and most efficient process for single-sided grinding because of its ability to quickly remove stock from one side of a part. It replaces double disc grinding which generally has size restrictions.
There are many advantages to Blanchard grinding. Usually the potential benefits are multiple, in other words you generally receive more than one of the listed benefits. Some common benefits are: size versatility, part to part tolerance consistency (thickness), greater ability to achieve flatness and close parallel tolerances, elimination of parting lines, and stable RMS finishes.
Blanchard grinding is an effective grinding method for simultaneous grinding of small and large parts. It is the most economical and proven method for large stock removal. Because greater horsepower is used for grinding, costs related to pre-machining and turnaround times can be reduced substantially.
Blanchard grinding is a serious economical savings tool
for heavy stock removal regardless if it is ferrous or non-ferrous.
The trademark cross-hatched finish will give RMS ranges from 32 -125 though
finer finishes can be achieved.
Preface To Facts & Troubleshooting Guide
We at Systec are always striving to educate our customers to the proper use, correct safety, and fundamental facts relating to the grinding process. We hope to achieve this by a fact and question section followed by a response or answer. We always have felt that an educated user is beneficial to both of us. Unless we are product specific, the information that you read about will be general information that is pertinent to most grinding issues be they tool room, surface grinding, cylindrical or cut-off grinding or segmental grinding. There will be no defined order of importance of the questions or topics. We will continually upgrade this section with new information so that you eventually will have an encyclopedia of information that we hope will be useful. Feel free to contact us with any suggested topics.
Table Of Contents:
1. Grain Types
2. Grit Sizes
9. Chuck Repair
12. Work Speed
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1. Grain Types (12-04-2004)
Fact & Question: There are four basic abrasive grains used in grinding: aluminum oxide, silicon carbide, Zirconia alumina, and ceramic. They all have different characteristics and colors. An ongoing question is does color of the grinding wheel mean anything?
Answer: Different grains can be used by themselves or in combination with one another to achieve required results. Sometimes grains will be dyed or baked to certain temperatures which will affect their color. While color can indicate types of grain it is not an all inclusive method, but it is a good starting point. It often helps in identifying grain combinations to have the color information available.
Fact & Question: Grains come in different screen sizes called grit size. Coarser grits are bigger and considered more aggressive. Fine grits are less aggressive and generally give better finish. What are the most popular grit sizes and where would you use coarse and fine grit segments?
Answer: Grit sizes range from 4 to 1200. Most aggressive grinding is done in the coarse (4-46grit) range and finish grinding is accomplished in the finer grits (60-120 grit). Most segments used for aggressive grinding are made from grain ranges 24 grit to 36 grit. For better finish 46 grit to 80 grit is used. Very seldom are segments made over 80 grit. They would load the segment and/or burn the parts too easily. Many times combinations of grits will be used to facilitate the need for grinding aggressively and still maintaining finish.
3. Term for Blanchard Grinding (7-06-2005)
Fact & Question: I hear the term Blanchard™ grinding used often. Does this refer to a stone or a company?
Answer: Both. There are many brand names that over the time have become associated generically to a product. Crescent™ wrench is really an adjustable wrench. Kleenex™ is really a face tissue. Blanchard stones are really segments for vertical spindle machines. Today, Blanchard™ makes machinery but the stones are now made by a west coast manufacturer of grinding wheels. Systec manufacturers’ Blanchard type segments in many styles, grits and grain combinations.
4. Most Popular Styles (09-25-2005)
Fact & Question: There are many different styles of segments. The style needed is determined by the chuck which is installed on your vertical spindle grinding machine. What are the most common styles?
Answer: The 80/20 rule applies. 80% of the segments used can be found in 5 styles. From our perspective we would rate the popularity of those five in order of most used to least used as:
Cortland Chuck (CD)
Norton Mattison Chuck (NO)
Sterling (ITT Abrasive Products) (STG)
Abrasive Associate (Ferro) (AA-1)
Hanchett Chucks (Red Anchor) (RA)
5. Cortland Sizes/Styles (10-27-2005)
Fact & Question: Cortland segments are the most popular style of segment. Sometimes it is confusing because of the styles that are available. What are the general styles of Cortland segments and what is their related size?
Answer: Cortland segments are generally divided into 5 categories which represent 5 sizes. They are:
CDL 11-1/4 x 2-1/4 x 6
CDTL 11-1/4 x 3 x 6 (not very popular)
CDXL 11-1/4 x 2-1/4 x 8
CDXT 11-1/4 x 2-1/2 x 8 (not very popular)
CDTXL 11-1/4 x 3 x 8 (sometimes called a bonus segment)
6. "Set" numbers (10-27-2005)
Fact & Question: Cortland segments, like other segments, can also be identified by a set number. What does the set number represent?
Answer: The set number for Cortland’s are generally not used anymore because most of the chucks that represented those segment sizes are out of service or just plain obsolete. When customers order a particular set (CD10) we require that they give us the physical dimensions of that segment because 99% of the time they really do not want that particular size but the number of segments that comes with a set of that size. For example, a CD10 has a physical measurement of 6-1/2 x 1-1/4 x 4. There are four to a set. In twenty years of manufacturing segments we have never been asked to make a CD10 with those dimensions but we have had many people reference that number. That is why we always ask for a physical dimension when someone refers to a Cortland set number.
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