HTML (Hypertext Markup Language)
HTML (Hypertext Markup Language) is a text-based approach to describing how content contained within an HTML file is structured. This markup tells a web browser how to display text, images and other forms of multimedia on a webpage.
HTML is a formal recommendation by the World Wide Web Consortium (W3C) and is generally adhered to by all major web browsers, including both desktop and mobile web browsers. HTML5 is the latest version of the specification.
How HTML worksHTML is a text file containing specific syntax, file and naming conventions that show the computer and the web server that it is in HTML and should be read as such. By applying these HTML conventions to a text file in virtually any text editor, a user can write and design a basic webpage, and then upload it to the internet.
The most basic of HTML conventions is the inclusion of a document type declaration at the beginning of the text file. This always comes first in the document, because it is the piece that affirmatively informs a computer that this is an HTML file. The document header typically looks like this: <!DOCTYPE html>. It should always be written that way, without any content inside it or breaking it up. Any content that comes before this declaration will not be recognized as HTML by a computer.
Doctypes are not just used for HTML, they can apply to the creation of any document that uses SGML (Standard Generalized Markup Language). SGML is a standard for specifying a specific markup language being used. HTML is one of several markup languages that SGML and doctype declarations apply to.
The other critical requirement for creating an HTML file is saving it with a .html file extension. Whereas the doctype declaration signals HTML to the computer from the inside of the file, the file extension signals HTML to the computer from the outside of the file. By having both, a computer can tell that it's an HTML file whether it's reading the file or not. This becomes especially important when uploading the files to the web, because the web server needs to know what to do with the files before it can send them to a client computer for the inner contents to be read.
After writing the doctype and saving as an HTML file, a user can implement all the other syntactic tools of HTML to customize a web page. Once finished, they will likely have several HTML files corresponding to various pages of the website. It's important that the user uploads these files in the same hierarchy that they saved them in, as each page references the specific file paths of the other pages, enabling links between them. Uploading them in a different order will cause links to break and pages to be lost, because the specified file paths will not match the pages.
Basic elements of HTMLUsing HTML, a text file is further marked up with additional text describing how the document should be displayed. To keep the markup separate from the actual content of the HTML file, there is a special, distinguishing HTML syntax that is used. These special components are known as HTML tags. The tags can contain name-value pairs known as attributes, and a piece of content that is enclosed within a tag is referred to as an HTML element.
HTML elements always have opening tags, content in the middle and closing tags. Attributes can provide additional information about the element and are included in the opening tag. Elements can be described in one of two ways:
Pros of using HTML include:
A few cons to consider are:
HTML tags dictate the overall structure of a page and how the elements within them will be displayed in the browser. Commonly used HTML tags include:
As mentioned, there are opening and closing tags that surround the content they are augmenting. An opening tag looks like this: <p>. A closing tag is the same but contains a backslash in it to indicate that it's the end of the given HTML element. Closing tags look like this: </p>.
How to use and implement HTMLBecause HTML is completely text-based, an HTML file can be edited simply by opening it up in a program such as Notepad++, Vi or Emacs. Any text editor can be used to create or edit an HTML file and, so long as it is named with an .html file extension, any web browser -- such as Chrome or Firefox -- will be capable of displaying the file as a webpage.
For professional software developers, there are a variety of WYSIWYG editors to develop webpages. NetBeans, IntelliJ, Eclipse and Microsoft's Visual Studio provide WYSIWYG editors as either plugins or as standard components, making it incredibly easy to use and implement HTML.
These WYSIWYG editors also provide HTML troubleshooting facilities, although modern web browsers often contain web developer plugins that will highlight problems with HTML pages, such as a missing closing tag or syntax that does not create well-formed HTML.
Chrome and Firefox both include HTML developer tools that allow for the immediate viewing of a webpage's complete HTML file, along with the ability to edit HTML on the fly and immediately incorporate changes within the internet browser.
HTML, CSS and JavaScriptHTML is used to create webpages but does experience limitations when it comes to fully responsive components. Therefore, HTML should only be used to add text elements and structure them within a page. For more complex features, HTML can be combined with cascading style sheets (CSS) and JavaScript (JS).
An HTML file can link to a cascading style sheet or JS file -- usually at the top of the document with a specified file path -- which will contain information about which colors to use, which fonts to use and other HTML element rendering information. JavaScript also allows developers to include more dynamic functionality, such as pop-ups and photo sliders, in a webpage. Tags called class attributes are used to match HTML elements to their corresponding CSS or JS elements.
For example, if a user wants the color of a certain amount of text to be red, they can write code in the CSS file with an accompanying class attribute that turns text red. Then they can place the associated class attribute on all the pieces of text they want to be red in the HTML sheet. The same basic method applies to JS sheets, with different functions.
Separating information about how a page is structured, the role of HTML, from the information about how a webpage looks when it is rendered in a browser is a software development pattern and best practice known as separation of concerns.
History and developmentIn the early days of the world wide web, marking up text-based documents using HTML syntax was more than sufficient to facilitate the sharing of academic documents and technical memos. However, as the internet expanded beyond the walls of academia and into the homes of the general population, greater demand was placed on webpages in terms of formatting and interactivity.
HTML 4.01 was released in 1999, at a time when the internet was not yet a household name, and HTML5 was not standardized until 2014. During this time, HTML markup drifted from the job of simply describing the document structure of webpage content into the role of also describing how content should look when a webpage displays it.
As a result, HTML4-based webpages often included information within a tag about what font to use when displaying text, what color should be used for the background and how content should be aligned. Describing within an HTML tag how an HTML element should be formatted when rendered on a webpage is considered an HTML antipattern. HTML should generally describe how content is structured, not how it will be styled and rendered within a browser. Other markup languages are better suited to this task.
One major difference between HTML4 and HTML5 is that the separation of concerns pattern is more rigorously enforced in HTML5 than it was in HTML4. With HTML5, the bold <b> and italicize <i> tags have been deprecated. For the paragraph tag, the align attribute has been completely removed from the HTML specification.
HTML versionsThe following is a list of HTML versions and the years they were created. Several iterations of each version have been released over time. This list aims to focus on significant iterations.
HTML5 introduces several elements to increase interactivity, multimedia capabilities and semantic efficiency. Instead of using plugins, multimedia can be placed within the HTML code. These elements include:
Other main features of HTML5 include:
While the addition of these features represents an effort to support multimedia embedding, changes to the HTML specification demonstrate the desire of the community for HTML to return to its original purpose of describing the structure of content. Basically, more structural features have been added, while several format-centric features have been deprecated. For the purpose of backward-compatibility, web browsers will continue to support deprecated HTML tags, but eventually HTML will be mainly structure-based.
HTML syntax standardsIn the following HTML example, there are two HTML elements. Both elements use the same paragraph tag, designated with the letter p, and both use the directional attribute dir, although a different attribute value is assigned to the HTML attribute's name-value pairing, namely rtl and ltr.
Notice that when this HTML snippet is rendered in a browser, the HTML tags impact how each HTML element is displayed on the page, but none of the HTML tags or attributes are displayed. HTML simply describes how to render the content. The HTML itself is never displayed to the end user.
In order for a web browser to display an HTML page without error, it must be provided with well-formed HTML. To be well-formed, each HTML element must be contained within an opening tag -- <p> -- and a closing tag -- </p>. Furthermore, any new tag opened within another tag must be closed before the containing tag is closed. So, for example, <h1><p>well-formed HTML</p></h1> is well-formed HTML, while <h1><p>well-formed HTML</h1></p> is not well-formed HTML.
Another syntax rule is that HTML attributes should be enclosed within single or double quotes. There is often debate about which format is technically correct, but the World Wide Web Consortium asserts that both approaches are acceptable.
The best advice for choosing between single and double quotes is to keep the usage consistent across all the documents. HTML style-checkers can be used to enforce consistent use across pages. It should be noted that sometimes using a single quote is required, such as in an instance where an attribute value actually contains a double quote character. The reverse is true as well.
It's important to note as well that the language HTML works with is basic English. Non-English characters -- or letters -- such as Chinese, or special symbols -- like letters with accent marks -- may not display correctly on a webpage by default. In order to accommodate special character sets, users need to specify the character encoding with an element that looks like this: <meta charset="utf-8"/>. In this case, utf-8 is the character set. Utf-8 is HTML's default English charset.
Closing the Skills Gap With Sheet Metal Fabrication
New technologies are blurring the lines between CAD/CAM software and equipment to overcome training gaps, enabling more manufacturers to enter sheet metal fabrication. However, even with this technology, following best practices in part design is essential to ensuring that components function as intended. For instance, ensuring there’s enough space around features and providing manufacturers with a 3D file of your part will help ensure your parts are robust and created to your specifications.
Changing Metal Fabrication LandscapeNewer CAD-embedded presses, punches, and sheet metal brakes are replacing increasingly difficult-to-access training to enable companies to start fabricating faster. These machines use a 3D CAD design or digital twin to extrapolate a flat pattern, but that’s not all. They also give their operators feedback, training, and step-by-step instructions on how to fabricate a sheet metal part, including which tools are needed and how to place workpieces in the machine. They can even prevent a user from making mistakes in fabrication.
Machinery like this is more crucial than ever to overcome accessibility barriers to one of the least expensive manufacturing methods. Fabricating is often cheaper than milling, and it scales well in volume production. It also is effective for large parts, and it provides parts of all sizes with a high strength-to-weight ratio. However, specialized fabrication knowledge has traditionally been limited to CAD designers and machine operators, requiring years of training and experience. Now, fabrication apprenticeship and training programs are vanishing, making learning these skills through training even more difficult. This is where these machines come in; they help to augment knowledge so those with less training can also enter the field.
For companies that can afford these machines (which can cost five times the price of a traditional one) the investment allows them to catch up on traditionally tribalized knowledge and quickly start production. For one company in our manufacturing network, this machinery enabled them to expand their range of services beyond laser cutting and start offering bending and other sheet metal fabrication services using online tutorials and the machine’s guidance. The equipment and digital tools caught them up on the skills they needed immediately. While suppliers now have these machines to help them, however, there are still certain design best practices to keep in mind to ensure the final parts come out exactly to your specifications. What does a manufacturer need from a designer to make their part successfully? What are the best design tips for sheet metal? Read on and find out.
Your Flat Pattern (Alone) Is WrongFlat patterns will often assume a generic bend radius and K factor, which aren’t always accurate. Bend radius is always measured from the inside of the bend. K factor is defined as the ratio of the material’s neutral axis to its thickness. The neutral axis represents the transition area between the two effects that will occur during bending—compression and expansion. It’s the one place where no material is stretched (as on the outside of the bend) or compressed (as on the inside of the bend).
While most people will use programs like SolidWorks or Autodesk Inventor to create an unfolded version of their parts to be cut out, it’s crucial to understand that no software is 100% accurate. Manufacturers need to see the 3D model to understand what is critical for your part to be formed. K factor deviates depending on whether you’re using air bending, bottom forming, coining, or other techniques. Modern manufacturing software can calculate the proper ways to bend the material more effectively than programs like SolidWorks, so the manufacturer can “unfold” your design on their side and find the best steps to make it as you intended. To ensure the flat pattern is more accurate, manufacturers will also utilize lookup tables and calculators online for the K factor and input the more exact values into the CAM program.
Tip: Remember for 90-degree bends, the top die will be at an 88-degree angle to account for spring back. If you’re using a 90-degree angle, you’re likely doing bottom bending, so it’s best to use the bottom bending numbers when referencing K factor tables.
Notes on Design for Individual FeaturesThe most common features designed into sheet metal fabricated parts include bends, holes, slots, and flanges and lugs. The table below shows the recommended number of material thicknesses that any feature should be set away from other features (for example, an edge should be at least 2x the material’s thickness in length away from a hole). Note that a flange in this case is the same as a bend edge.
Table courtesy of Xometry![Sheet Metal Feature Clearances in Material Thicknesses[50].jpg](/sites/cet.com/files/Sheet%20Metal%20Feature%20Clearances%20in%20Material%20Thicknesses%5B50%5D.jpg "Sheet Metal Feature Clearances in Material Thicknesses[50].jpg")
Sheet metal feature clearances (in material thickness).
Bending Design
The first thing to remember for bending design is that you will need to include information on whether your part's inner or outer dimensions are more important. For example, external dimensions will be crucial if your part must fit inside something else, while inner dimensions will be important if you’re planning to fit other things inside it. Don’t include both inner and outer part dimensions without specifying which ones are more important, though—software will often ignore the fact that the material has thickness as well as width and length.
It’s also important to remember that tolerances are not constant. Multiple bends, types of bend angles, holes, and even linear dimensions and diameter will affect them. A general rule is that you want to maintain a ratio of 1:1 material thickness to a bend, so for a 1-inch-thick plate you’ll want at least an inch on the internal radius on the bend. If you have no other choice, a bend can even be 1/32nd under the material’s thickness. However, this adds risk unless you’re using specialized tooling, so it’s best to go with higher radii.
Tip: To save time and money, make bends identical. Doing the same bend twice can be part of a single operation, so it will save time in adding multiple die setups.
Lug and Flange DesignFor lugs and flanges, try to ensure that the material’s grain direction is perpendicular to the bend. Otherwise you’re at greater risk of cracking the material. Flange length should be about 4x the material thickness at a minimum, both for safety and ease of manufacturing. Bending with a brake (which uses a V-shaped block) requires the metal to be long enough to extend along both sides of the V for support. Shorter flanges may need to be pulled instead of bent.
Hole and Slot DesignIt’s common for manufacturers to see designs where holes and slots are placed too close to edges. As the table above notes, you’ll want any hole to be located at least 2x the material thickness away from an edge and 2.5x the thickness away from a bend edge. A slot should be 4x the material thickness away from a bend edge. If these features end up too close to a bend, they can be distorted from the stress in the material.
If a hole or slot must be within those widths to a bend, notch relief cuts can be used to maintain the feature’s integrity. Otherwise, holes can become ovals or the lip closest to a bend will flare out. These distortions will make it especially difficult to install hardware in that hole later.
Relief-Cut DesignEvery time you bend, you increase stress on the material, so relief cuts allow you to limit the stressed areas on a part. These cuts may come in the form of notches across the material's surface. Other relief cuts into the sides of the material (either as notches or circles) will relieve bulging when it’s folded. These cuts or notches should also be wider than the material’s thickness.
For features such as holes and slots, notch-relief cuts can help avoid having those features flare outward at the edge nearest to where the part is being bent. If you want to protect the flatness of an area with a hole, you can do a square of relief cuts around it.
Countersink DesignYou can also add countersinks to a part, though you want to avoid counterbores. Countersinks and counterbores are used in attaching fasteners or for deburring. A counterbore will require CNC milling, adding expense and complications. Countersinks can be up to 60% of the material’s thickness deep, and they should be at least 8x the material’s thickness away from the edge or a hole or slot.
Corner-Fillet DesignCorner fillets should be at least half the material thickness, both for internal and external fillets. These features are commonly included for welding, for safety considerations (to avoid injury from sharp edges), or for aesthetic purposes.
Forming and Stamping DesignForming and stamping will add additional shape to your part. These processes can be used to create gussets (which act like ribs), joggles (which offset the plane by one material thickness), hems (which help stiffen your part), louvers, curls, external curves, and forming wraps. If possible, aim for angular features since they’re less expensive to create.
Forming and stamping both require die sets, so creating them will increase upfront costs. Your initial lead time will increase as well, owing to the extra time required for die fabrication. Stamping is better for higher production runs, as you can add multiple features using a single operation, lowering the unit cost over larger production volumes.
Working Toward Metal Fabrication SuccessKeeping to these best practices will help both machines and their operators fabricate the exact parts you need, whether they’re experienced fabricators with standard machines or those using advanced smart machines to aid and speed up production.
This handy UX design cheatsheet is invaluable
UX design in motion principles
Design is a science as much as an art, and UX design is one of the areas where that is, or at least should be, extremely apparent. UX design is about crafting experiences that work for users, with form subservient to that experience.
You might be familiar with Disney's 12 principles of animation, which set out a kind of rule book for creating moving images, whether it's for films and cartoons, CSS animations or UI design. The wonderful cheatsheet below takes that concept but updates it for the scientific requirements of UX, providing 12 principles for UX design in motion.
Principles of UX design in motion
This motion UX design crib sheet was devised to accompany a manifesto drawn up by Issara Willenskomer back in 2017. Disney is dead, he claimed, proposing 12 principles for UX design in motion: easing, offset and delay, parenting, transformation, value change, masking, overlay, cloning, obscuration, parallax, dimensionality and dolly and zoom. In turn, he split these into four categories: timing, object relationship, object continuity, temporal hierarchy and spatial continuity.
Willenskomer was adamant that UX in motion is not UI animation. By that he meant, that it's something more fundamental, not just a superficial afterthought intended to make an experience prettier or more engaging. It actually adds value to the underlying UX design and supports usability by creating continuity, narrative and relationships.
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UX Links recently shared a review of these UX principles in a Twitter thread with a tweet for each principle, complete with a gif as an example and comments on why each principle works and how it can be implemented. Each tweet provides a real-world example of the principle in action, shedding some more light on how the principles work in practice.
an image saying 'learn design with Creative Bloq' with two people next to it
Consider signing up for our UX design course to learn more about the subject. You might also want to tool up with the best UI design tools.