How to select a grinding wheel? Short, general answer. Depends on many variables. The most basic in general:.The harder the steel (material), the softer the wheel.The more stock to remove, the coarser the wheel.The finer finish required, the finer the grit.The sharper internal corner desired, the harder and finer the wheel to do just the corner. To go much beyond that, you would need to be specific as to material, machine, etc.
One thing to keep in mind. A grinding wheel is basically thousands of little cutters the same as other machine tool cutters. Many of the same rules apply to both.
You shouldn't have any trouble with the 410 but the aluminum will give you heartburn. It will want to collect in your wheel and eventually fly off in chunks and even take some or all of your wheel with it as well as leave ugly scars in your workpiece. One way to alleviate this condition is with liberal doses of beeswax to the periphery of the wheel. Beeswax used to be available in stick form from many industrial suppliers.
Can't tell you if it still is. Keep applying it as you grind.
It wants to melt as it gets heated. If you don't have variable speed use a small diameter wheel. Less heat is generated. I'm assuming you're dry grinding. Don't know much about wet grinding. If you're wet grinding, straight honing oil might be better than mixed coolant. Thats a guess.
It's great to have a separate grinding forum. I've done some plain Jane surface grinding and been around some pretty good mold makers/grinder hands but have never picked up a very good knowledge base. In the home shop, I have a Boyar-Schultz 6x12. I do all my grinding dry. So The first question: what is a good all-around wheel for softer steels: unhardened O-1, 4140 PH, and cold-rolled?
Secondly, like VSMI I also have a project that calls for grinding 6061 aluminum so I'm also looking for tips/wheel selection advice on that. Lurk mode off. Novice question here, but the selection of wheel is said to be determined by (among other things) the hardness of the steel being ground. So to be sure I'm getting the concept, the idea is that one would choose a different wheel for steel that is not heat treated, such as ordinary cold rolled steel, or leaded steel, and then a different wheel when the steel is high carbon steel that has been heat treated - and that further the wheel grade might be further influenced by the rockwell number of the steel being worked on.
Is this a fair approximation of the idea? Jim Lurk mode on. I like Winterthur wheels in the OD Grinding area. We use a 53A and cuts 416ss and 4340 very well. This wheel will cut 17-4ph @H900 and does just okay on 303ss.
ID grinding wheel we like Cincinnati Wheels that are a Ruby/Aluminum Oxide. They cut 304ss pretty good. The parts still gets warm but it does better than any others we have tried. Centerless Grinding Wheels, I like two different wheels 22A Cincinnati Wheels and WZ100 Jowitt Rodger.
The Jowitt is a Resin type wheel and it works great on thin walled tubing. Now for SG wheels from Norton, I really don't like the wheels for anything but Surface grinding. A ceramic wheel takes to much wheel pressure to make a cut correctly. That is why it works well on surface grinding but you can't put a lot of wheel pressure in a OD or Id application. I need to surface grind some 6061T6 aluminum and 410 stainless assemblies such that a pocketed stainles insert must be flush with its aluminum housing, and all must be flat to 0.0003'/ft.
I've talked to two different Norton folks and got different answers, and neither made me feel very confident in their recomendations. There is about twice the amount of stainless to grind than aluminum. What do you think?? 12:00 AM I have ground a fair amount of non ferrous material (aluminum, bronze) and use a silicon carbide wheel from Norton (37C black stone variety) with liberal amounts of WD40 as a cutting fluid but never when it was married to a dissimiliar metal but I would try it if it were mine.
Also for selecting types of wheels, when i grind core pins on the surface grinder i plunge grind and, i find the shorter the contact area the harder the wheel needs to be, even if its 50 RC, i use 60k whenever i have less than.25 of the wheel tounching. Leaves a nice sharp corner. This is a 1' thick wheel. For most steel i find 46I will do just about everything.
I'll bump up to a 60 to hold a better corner. Has anyone tried those red wheels from norton? Any advantage over the 32A high performance AO?
Most obvious is the apparent lack of workholding. The part just lies between the regulating and grinding wheel seemingly free to exit the cutting zone at will. Yet it doesn't—usually. So how does centerless grinding work, and what are essential components that need to be understood to achieve successful part processing, consistently and predictably? We visited 's Milford, Ohio, technical center where it handles application development and service of the Landis Cincinnati line of centerless grinding machines.
We spoke with Greg Payne, the company's bid and proposal manager, about the fundamentals of centerless grinding specifically, why the process works and how understanding that translates into successful part processing. What Is Centerless Grinding? Centerless grinding is an OD grinding process. It differs from other cylindrical processes in that the workpiece is not mechanically constrained. On traditional OD machines, the work is held between centers or chucked and rotated against the faster spinning grinding wheel by an external motor usually located in a workhead. Unlike center-type or chucker-type grinding, parts made using a centerless process do not require center holes, drivers or workhead fixtures.
Instead, the workpiece is supported on its own outer diameter by a workblade located between a high speed grinding wheel and a slower speed regulating wheel with a smaller diameter. It's the relationship among these three basic components—grinding wheel, regulating wheel and workblade—that makes the difference between a successful centerless grinding application and one that gives headaches and bad parts. Why Centerless Works In cylindrical grinding, understanding the process is relatively straightforward. A workpiece, supported by centers or a chuck, is rotated against the grinding wheel, which is fed in a prescribed distance radially (plunge grinding) or traversed axially across the workpiece to create the desired OD dimension. Creating roundness from out-of-round conditions is the claim to fame of the centerless grinding process. It does this by virtue of the relationship among the grinding wheel, regulating wheel and the workblade. Side-viewed, from the operator's perspective, the centerless grinder has the grinding wheel on the left, workblade in the middle and the smaller diameter regulating wheel on the right.
For most applications, the centerline of the grinding wheel and regulating wheel are in the same plane, at equal heights above the machine bed. To achieve rounding action, the workblade must be set so that the centerline of the workpiece is above the centerline of the grinding and regulating wheels. This is a critical relationship for successful centerless grinding. If the workpiece rests on a flat workblade that is on center with the regulating and grinding wheels, the contact points form three sides of a square.
As the part is ground in this setup, any high spot on the workpiece will shift the work slightly on the blade, allowing the grinding wheel to cut a directly opposite low spot. Over time this setup will create three lobes on the workpiece that may be dimensionally accurate but far from round. Setting an angled workblade so it slopes toward the regulating wheel and supports the workpiece centerline above the centerline of the regulating and grinding wheels is how the centerless operation is able to generate roundness. In this setup if a high spot comes in contact with either the blade or the regulating wheel, it does not create a directly opposite low spot because of the angle created between the centerlines of the wheels and workpiece.
Instead of grinding a lobe shape in the workpiece, the high spot is gradually reduced by the action of the grinding wheel. So rather than creating a low spot on the periphery of the work equal to the high spot, the grinding wheel generates a proportionally smaller low spot at its contact with the workpiece. To better visualize this rounding action, imagine a workpiece with several high spots.
Now imagine that part being ground with only a single rotation. When the part is removed, it would show only the high spots had been touched.
The angle of the workblade helps keep the workpiece in contact with and under the control of the slower rotating regulating wheel to resist any tendency to 'spin up' to the speed of the grinding wheel. In some cases, a spin-up can take a workpiece from 850 rpm to near 60,000 rpm in the blink of an eye. This is not something you want to have happen. A rule of thumb for setting the correct height for a workpiece that is up to 1 inch in diameter is to have one half of the workpiece diameter above the centerline of the grinding and regulating wheels. So, for a 1 inch diameter workpiece, the height should be a half inch above the wheel's centerline. 'This is the primary starting point for most centerless grinding setups,' says Mr. Most centerless grinding machines give the distance from the top of the lower slide to the centerline of the grinding wheel and regulating wheel as one of the specifications.
For example on Cincinnati's DE model centerless grinders, this distance is 9.875 inches. Payne points out that this measurement varies among machine manufacturers and models. With this known dimension, the next step to get the correct blade height calculation is to add the workpiece height above center to the distance between the slide and wheel centerline. For a 1 inch diameter workpiece on a Cincinnati DE model, the workpiece center height needs to be 10.375 inches measured from the lower slide. 'There are numerous ways to get this measurement,' says Mr. 'Ultimately though, the machinist needs to end up with one half of the workpiece above the centerline of the wheels, resting one-third of the way down from the top of an angled workblade and against the regulating wheel.
This will provide good rounding action and stable grinding conditions.' Centerless grinding workblade angles range from 0 to 45 degrees. For most centerless grinding applications, a top blade angle of 30 degrees seems to provide the best results. 'The basic rule is the steeper the angle of the blade the faster the rounding action,' says Mr. 'There are limits, however.
For larger diameter and longer work, a shallower blade angle is best. Choosing 30 degrees is a good general starting point for top blade angle.' Also, setting the regulating wheel slow, at about 30 rpm, is a point to begin optimizing the centerless grinding process. Obviously, this regulating wheel rotation speed is dependent on work diameter and stock removal rates required. But 30 rpm is a good place to start. The workpiece is placed between the wheels, and the grinding cycle begins.
After spark-out, the finished part is removed and the next one goes in. Infeed centerless grinding is analogous to plunge grinding on a center-type machine in that the workpiece is static in the axial direction. RFor continuous, production-type centerless grinding, the thrufeed method is very effective. Thrufeed grinding is accomplished by passing the workpiece between the grinding and regulating wheel. Basically, raw material goes in one side of the grinding zone, and finished workpieces come out. The work is driven axially between the wheels by inclination of the regulating wheel relative to the grinding wheel.
Because all of the points to be ground on the workpiece contact all the points on the wheels, this centerless grinding method is best applied to straight cylindrical parts without shoulders or other interfering features. In thrufeed grinding, the regulating wheel is inclined, creating a feed angle relative to the grinding wheel. This feed angle allows the regulating wheel to perform the dual purpose of rotating the workpiece against the grinding wheel and driving the workpiece across the face of the grinding wheel. The regulating wheel can be swiveled relative to the grinding wheel. However, to do its job and use the full width of the grinding wheel, line contact between the workpiece, grinding wheel and regulating wheel must be m˜aintained.
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Therefore, the regulating wheel must be trued with a diamond block located on the truing attachment. The diamond block is a device that adjusts the diamond contact relative to the workpiece height above the grinding and regulating wheel centerline. 'A quick check to see if the thrufeed setup is running correctly,' says Mr. Payne, 'is to look at the wear line across the top of the workblade. This line should be parallel to the top of the blade. If it runs uphill, from front to back, there is too much diamond block offset. It's the opposite if the line runs downhill.'
Is Centerless Grinding For You? Traditionally, centerless grinding is found in shops involved in high volume production runs. That's still an important segment for the technology. Increasingly, though, the advantages of centerless grinding, such as rapid rounding and accuracy, are finding application in shops that run relatively shorter job lot sizes. The enabler for this is the application of CNC and servomotor technology to the centerless grinding machine. With electromechanical actuation of slides, dressers and truing attachments, setup of the centerless machine is a much less daunting and time consuming exercise. Moreover, the ability to program grinding and regulating wheel contours using CNC actuated truing attachments eliminates the need for profile cams, which take time to manufacture and are usually less accurate.
Centerless grinding is successfully applied to manufacture of parts ranging from hypodermic needles to bowling balls. The principles of the process remain the same regardless of the workpiece. Like most metalworking processes, centerless grinding is not magic, if you understand the fundamentals.
I run a kellenberger 1500 U at a die shop. I was originally a lathe guy but took on this position when the head grinder retired. I was taught under the method of if its not working, change things until they do. I was never taught to even balance a wheel or proper dressing etiquette and had to learn alot on my own. I don't want to sound green, but I still am. My standard tolerances are +/.
0002 on diameter but I routinely grind locating pins to +/. We recently purchased a Jones and shipman suprema 650. Its a quirky machine and does okay.
The problem is that I have no clue where to start on feeds and speeds as what works manually doesn't translate. Right now I grind by 'feel' and with the cnc I can only feed rate override mid cycle. Most of my parts are hardened 4140, 4150, S-7, D-2, or O-1. Now I am getting into taper grinding and while my parts are coming out good, my cycle times are far to long for us to be profitable. Is there a definitive guide to OD ID grinding that's more advanced with possibly some cnc thrown in?
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And tips for taper grinding?
US5824294A - Sand removing body powder - Google Patents Connect public, paid and private patent data with Sand removing body powder Info Publication number US5824294A US5824294A US08950689 US95068997A US5824294A US 5824294 A US5824294 A US 5824294A US 08950689 US08950689 US 08950689 US 95068997 A US95068997 A US 95068997A US 5824294 A US5824294 A US 5824294A Authority US Grant status Grant Patent type Prior art keywords composition sand body cornstarch powder Prior art date 1997-10-15 Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Expired - Lifetime Application number US08950689 Inventor Trevor David Abramson Adele Abramson Original Assignee Abramson; Trevor David Abramson; Adele Priority date (The priority date is an assumption and is not a legal conclusion. A body powder composition useful for removing sand adhered to a user's body. The composition comprises a major amount of cornstarch.
A related method for removing sand off the body is also disclosed comprising the steps of liberally applying a powder composition containing a major amount of cornstarch to an area of the body having sand adhered thereto; rubbing said composition on said area; and wiping said composition and said sand off the area using one's hands or a towel or the like. FIELD OF THE INVENTION The present invention relates to body powder compositions and, more particularly, to a cornstarch body powder composition useful in removing sand from the skin. BACKGROUND OF THE INVENTION Body powders have long been available to the consuming public, primarily for absorbing moisture and body oils from the sebaceous and sweat glands. Body powders have also been used extensively on babies to help prevent diaper rash and to otherwise help maintain dryness. None of such prior art body powders have been utilized for the specific purpose of removing sand from the body. Beachcombers have long dealt with the problem of sand adhering to their bodies, especially their legs and feet, after swimming or sunbathing. Sand on the feet makes it difficult and uncomfortable to wear shoes or sandals.
It would therefore be an advantage in the art if there was a body powder composition which could be used upon leaving the beach to easily remove sand, allowing one to get dressed on the beach, without having to immediately shower. SUMMARY OF THE INVENTION It is an object of this invention to provide improved body powder compositions to remove sand from the body. It is another object of this invention to provide body powder compositions to remove sand having improved moisture absorbency and aesthetically pleasing fragrances. It is a further object of this invention to provide a method for removing sand utilizing cornstarch-based body powder. The foregoing objects and other features and advantages of the present invention are achieved by a composition comprising a major amount of conventional starch, preferably cornstarch. Other objects of this invention will be set forth in, or be apparent from, the following detailed description of the invention. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the use of body powder compositions containing from about 50-99% starch and from about 1-20% of baking soda, and may also contain other components normally utilized in such compositions.
Powder starches have been used for many years in dusting powder applications. While starches from various sources such as cornstarch, pregelatinized cornstarch, potato starch, sago starch, rice starch, tapioca starch and the like are commercially available, the most readily available form of starch for the desired use is cornstarch. Cornstarch is preferred since it has demonstrated skin affinity, uniform natural globular particle dimensionality and purity, as well as its ready availability. Most cornstarch normally produced for industrial, food and pharmaceutical uses is derived from field corn commonly known as yellow dent corn. This cornstarch consists of irregular angular white granules or fine powder of largely spherical to polygonal shaped particles. The particle size is such that not less than 99% passes through a 100 mesh screen and preferably at least 98% will pass through a 200 mesh screen.
This cornstarch is utilized in an amount from about 80% to 99% by weight of the total composition, preferably from about 90% to 97.5% by weight of the total composition. The pregelatinized cornstarch which is useful in the present invention is derived specifically from waxy maize corn. The pregelatinized cornstarch is cornstarch that has been chemically or mechanically processed to rupture all or part of the granules, preferably in the presence of water and subsequently dried. This pregelatinization of the cornstarch is achieved by well-known processing techniques in the starch industry. Generally, this process involves dispersing a cornstarch, preferably waxy maize cornstarch, into a dilute water slurry which is then doctored onto a drum drier internally heated by superheated steam. The surface temperature of the drum boils the slurry and simultaneously converts it to a pregelatinized form and also dries the boiled starch mixture into a film which is then stripped from the drum by a scraper blade.
It has now been found that subsequently milling or grinding this film forms flaky particles of particle size such that at least 80%, and preferably about 98%, passes through a 200 mesh screen. These particles should have a bulk density of from about 3.0 gm./cubic in. To about 7.0 gm./cubic in.
And a moisture content no greater than about 14% by weight and preferably no greater than about 7% by weight, to be suitable for use in the compositions of the present invention. The specific pregelatinized cornstarch is utilized in from about 1.0 to 20% by weight of the total composition, preferably from about 2.5 to 10%. Baking soda, or sodium bicarbonate, is also added to the composition in an amount of about 1-20%. Baking soda functions to reduce the odor of the composition, adjust its pH, assist in the removal of the sand, and improve the texture of the composition. Other components normally found in body powder compositions can be added if desired. Such components include flow agents such as tricalcium phosphate, dyes and colorings, bactericides, fungicides, medicaments and perfumes.
The perfumes or fragrances which are useful in the present invention include any commercial perfume which results in the fragrance desired by the formulator of the powder compositions. Commercial perfumes are a mixture of many components and these components all contribute to the particular fragrance which is characteristic of the mixture.
In obtaining the desired fragrance, the ratio of components might be changed, some components may be added and some omitted. Wiping said composition and said sand off the area using one's hands or a towel or the like.
We can calculate the steel charge volume of a ball or rod mill and express it as the of the volume within the liners that is filled with grinding media while the. In grinding selecting calculate the correct or optimum ball size that allows for the best and optimum ideal or target grind size to be achieved by your ball mill. Modification of the ball charge this calculator analyses the granulometry of the material inside the mill and proposes a modification of the ball charge in order to. Ball charge in ball mill download as pdf file pdf text file calculation of cement mill chargepdf ball mill grinding media max ball size calculation. Ball mill ball charge ball mill ball charger calculation for ball charging in iron beneficiation plant steel balls charge in ball mill zhengzhou hengxing.
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