Standards in this domain:
Know number names and the count sequence.
Count to 100 by ones and by tens.
Count forward beginning from a given number within the known sequence (instead of having to begin at 1).
Write numbers from 0 to 20. Represent a number of objects with a written numeral 0-20 (with 0 representing a count of no objects).
Count to tell the number of objects.
Scientific Toolworks Understand 5 Scientific Toolworks Understand 5.0 注册机 Understand 5.1.978 keygen Understand 5.1.978key Understand 5.1.978注册码 Understand 5.1.978激活 Understand 5.1. 1.5 T @50 Hz non oriented D (formerly B) ' non-alloy semi-finished (not finally annealed) E '. 1.0401 1.0453: C15D C18D: 1010 1018: CK15 C15 C16.8: 040A15 080M15 080A15 EN3B: C15 C16 1C15: S12C S15 S15CK S15C 1.0503 1.1191 1.1193 1.1194: C45: 1045: C45 CK45 CF45 CQ45: 060A47 080A46 080M46: C45 1C45 C46 C43: S45C S48C.
Understand the relationship between numbers and quantities; connect counting to cardinality.
When counting objects, say the number names in the standard order, pairing each object with one and only one number name and each number name with one and only one object.
Understand 5 1 1018 =
Understand that the last number name said tells the number of objects counted. The number of objects is the same regardless of their arrangement or the order in which they were counted.
Understand that each successive number name refers to a quantity that is one larger.
Count to answer 'how many?' questions about as many as 20 things arranged in a line, a rectangular array, or a circle, or as many as 10 things in a scattered configuration; given a number from 1-20, count out that many objects.
Compare numbers.
Identify whether the number of objects in one group is greater than, less than, or equal to the number of objects in another group, e.g., by using matching and counting strategies.1
Compare numbers.
Identify whether the number of objects in one group is greater than, less than, or equal to the number of objects in another group, e.g., by using matching and counting strategies.1
Compare two numbers between 1 and 10 presented as written numerals.
Llc 1018.1
1Include groups with up to ten objects. Wirecast pro 13 1 0 3.
The K-Factor in sheet metal working is the ratio of the neutral axis to the material thickness. When metal is bent the top section is going to undergo compression and the bottom section will be stretched. The line where the transition from compression to stretching occurs is called the neutral axis. The location of the neutral axis varies and is based on the material's physical properties and its thickness. The K-Factor is the ratio of the Neutral Axis' Offset (t) and the Material Thickness (MT). Below the image shows how the top of the bend is compressed, and the bottom is stretched.
The K-Factor is used to calculate flat patterns because it is directly related to how much material is stretched during the bend. It's used to determine Bend Allowances and Bend Deductions ahead of the first piece. Having an accurate idea of your K-Factor is key to designing good parts because it can anticipate Bend Deductions for a variety of angles without relying on a chart. Because of this it is often used by design software such as Solid Edge, Solid Works and Pro-Engineer, though Pro-Engineer uses a variation called the Y-Factor.
If you have a Bend Allowance (BA) you can derive the K-Factor from it. This is useful if you are transitioning from hand layouts to an advanced design software. Subsequently you can use the K-Factor to extrapolate allowances for new angles and radii.
Calculating the K-Factor
Since the K-Factor is based on the property of the metal and its thickness there is no simple way to calculate it ahead of the first bend. Typically the K-Factor is going to be between 0 and .5. In order to find the K-Factor you will need to bend a sample piece and deduce the Bend Allowance. The Bend Allowance is then plugged into the above equation to find the K-Factor.
- Begin by preparing sample blanks which are of equal and known sizes. The blanks should be at least a foot long to ensure an even bend, and a few inches deep to make sure you can sit them against the back stops. For our example let's take a piece that is 14 Gauge, .075', 4' Wide and 12' Long. The length of the piece won't be used in our calculations. Preparing at least 3 samples and taking the average measurements from each will help
- Set up your press brake with the desired tooling you'll be using to fabricate this metal thickness and place a 90° bend in the center of the piece. For our example this means a bend at the 2' mark.
- Once you've bent your sample pieces carefully measure the flange lengths of each piece. Record each length and take the average of lengths. The length should be something over half the original length. For our example the average flange length is 2.073'
- Second measure the inside radius formed during the bending. A set of radius gauges will get you you fairly close to finding the correct measurement, however to get an exact measurement an optical comparator will give you the most accurate reading. For our example the inside radius is measured at .105'
- Now that you have your measurements, we'll determine the Bend Allowance. To do this first determine your leg length by subtracting the material thickness and inside radius from the flange length. (Note this equation only works for 90° bends because the leg length is from the tangent point.) For our example the leg length will be 2.073 – .105 – .075 = 1.893.
- Subtract twice the leg length from the initial length to determine the Bend Allowance. 4 – 1.893 * 2 = .214.
- Plug the Bend Allowance (BA), the Bend Angle (B<), Inside Radius (IR) and Material Thickness (MT) into the below equation to determine the K-Factor (K). For our example it comes to
K-Factor Chart
A K-Factor will typically range between 0 and .5 for standard materials and thicknesses though smaller and larger K-Factors are possible. To help you begin I've included a K-Factor Chart below which contains common K-Factor starting points, good for general fabrication, for steel, aluminum and stainless steel.
| Radius | Soft / Aluminum | Medium / Steel | Hard / Stainless Steel |
|---|---|---|---|
| Air Bending | |||
| 0 - Mt. | .33 | .38 | .40 |
| Mt. - 3*Mt. | .40 | .43 | .45 |
| 3*Mt. - >3*Mt. | .50 | .50 | .50 |
| Bottom Bending | |||
| 0 - Mt. | .42 | .44 | .46 |
| Mt. - 3*Mt. | .46 | .47 | .48 |
| 3*Mt. - >3*Mt. | .50 | .50 | .50 |
| Coining | |||
| 0 - Mt. | .38 | .41 | .44 |
| Mt. - 3*Mt. | .44 | .46 | .47 |
| 3*Mt. - >3*Mt. | .50 | .50 | .50 |
The K-Factor of a 180° Bend (Hem)
The K-Factor for a 180° bend is going to be meaningless because it's tied to the Outside Setback which approaches infinity as the bend approaches 180°. Because of this K-Factors are not used to calculate allowances over 174°. Instead a hem allowance of 43% of the material thickness is used. See our post on Sheet Metal Hems for more information.
