There are the two main modeling modes, Parametric and Direct.
For me when I started out it was much easier to work in a direct modeling style. I didn't have to get confused with all the back and forth to different drawings and its easy to tweak and jigger with things.
For this I would start with end sketches of your main frame profiles(ie the angle Irons). Extrude them to length one at a time to create new components. you can either duplicate those or just create each one individually(can be easier and simpler when new to the software). once you've drawn and extrude each of the parts and they are all in the right locations, you can start looking at joining them to each other. and then conduct you testing.
when I build something from scratch I tend to not worry about making each individual component perfect I just get the right overall shape and size worked out and all the positions and such.(put another way, you can just sketch the entire profile of the upright then break it out into individual pieces later)Don't worry to much about properly modeled nuts and bolts or aesthetic detailing at this stage, you want a basically accurate and mechanically functional model at this point.
You can do all of this in a single model and file. create a new , you can create a new project in your home folder, then save your file in there. I usually tag this as "[project name]Design Master" . For most things this is all you need to start out but if you want to be a little more formal see the notes below.
File structures
If you later need or want to create individual components for manufacturing and documentation, create some folders in that project to place them in. I usually end up with the following sorts of folders created in my master project folder;
- Flat Parts (laser/water jet cut parts, ie parts that will need profiles generated)
- Machined parts(any thing that will need to be made in a machine shop or be cut to length or has holes drilled in it)
- Weldments(any parts that are welded/Glued composite of various pieces, may include pieces from other folders)
- Folded Parts(parts that require a folding operation)
- Hardware(any common components such as nuts, bolts, pins, washers etc, communist things that are purchased ready to use)
- Hardware Assemblies(use this folder to store pre assembled fastener sets)
- Specialty Parts(usually major components purchased and integrated into the project, may include other projects as well)
- Assemblies(these are assembled groups of parts that are used in the master assembly model, in particular these are used if certain assemblies are repeated multiple times in the master model like say legs or posts, these will reduce complexity and repetition in your master model and aid in BOM creation)
- Major assemblies(this is used if you have a project with major subsections say like a Car has Engine, chassis, suspension etc.)Sub assemblies(These are generally milestone incremental component assemblies like say the cylinder head, intake and block on an engine major assembly, again these help simplify your master model and make BOM breakouts more logical)
- Presentations(use this folder to store partial, modified or simplified models used to create renderings and drawings. those models not meant to be used for construction purposes)
- Old Stuff(I use this folder to dump old variants, dead ends, or other debris that normally builds up in your master project. You never kn ow when you might need them or have a fresh idea)
As a general note I also usually have a sub folder in most of these folders called "old stuff" or "unused". many times it can be a pain to break residual links to things you ended up not using in the final draft. this gives you a place to put them so they don't clutter up your working files. for example you may end up trying a number of different bolt nut washer combos over the span of the project so you might have 5 or 7 bolts only two of which you end up using in the end, stick them here and you don't have to spend hours figuring out how they are linked.)
General Design Process for manufactured projects(for non-experts)
When I design something this is the general work flow I use.(see disclaimer above)
- Create a project in your Home folder(or a new sub folder if it is part of a bigger set of related designs)
- Create a new model and set mode to direct modeling
- Create sketches of major component cross sections and extrude to create major elements (layout general shape, configuration and size of the model)
- begin to add any thread party elements for which you have or have made models for(ie McMaster components, motors, actuators etc). you goal being to start looking at the actual bits in relationship to one another so you can evaluate position, movement, interferences etc.
- Continue to refine the working elements of your model to ensure it will operate as intended. it sometimes helps to either articulate your components or just create test models showing the extremes of their motion so you can visualize where they want to be
- NOTE; at this stage I don't worry to much about my structural envelope unless I am working within a Hard volume or dimensional limitation. most focused on making it work as intended, packaging comes later in the process.
- Work with your components until your model can do what is intended(again less focus on layout more on function)
- Save that working model as a component and then duplicate it. with this new copy start playing with alternate layouts, orientations, linkages, components etc so you can get a feel for different options you have for achieving the same outcome. May help to start incorporating outside elements around your model to help determine constrains you may have.
- Now create a separate model that defines your envelope of avilability. this is a model that incorporates the environment in which the model will be expected to operate. it should be as accurate as possible showing any elements that might impact your models operation. things like protrusions, mounting points, other components, electrical feeds, output locations, access points, openings etc. You will use this to start building your working model. These things don't need to be overly detailed, just dimensionally accurate with a little wiggle on the large size(ie leave your self room for movement if needed, also consider tool access and how your model will be mounted leaving room to install fasteners etc. (also don't forget ground clearance when dealing with vehicles etc). Keep in mind that this envelope may change as you move forward so don't view it as the only option.
- Create a new master model and bring your design master and your envelope model. Use these to start fitting your concepts into with the goal to create a working layout of your functional elements. in other words find a layout and position were things work with the minimum of interferences.
- NOTE at this point I'm still not focused too much in mounting, frames, structure, ductwork, wiring piping etc just a working mechanically sound operation
- once you have a workable layout its time to start connecting it to the rest of the system. at this stage I start fitting in framework and other structures, exhaust ducts, drive elements, electrical conduits, covers, doors, filters etc. This stage can take some time and creativity you also may find that you have to try alternate components and in some cases Don't get discouraged if things don't all fit. you may need to go back to the customer to determine if there are options for more space or alternate locations. many times the envelope is somewhat arbitrary, kind of a "it would be nice if it fit in a 24" tool box sort of thing where it may be possible to change that to a 26" box or have a component outside that space. see what the model is telling you. Lastly don't try to get too precise or exact in your model representations at this stage. figure out where the hard edges are(ie mounting points and interactions with other elements like weed connections etc.)
- once you have everything there and in the defined space its time to start a process I call "Mastering". in this stage I start by systematically addressing each part and piece on its own. this is where you start adding in bolt holes, clearance notches, brackets, gussets, fittings, hardware. also start breaking up composite structural pieces into their individual components(ie angle irons, bars rods flat cut pieces, folded elements etc., break them down to their constiuent individual elements) during this process be saving any pieces to the correct folders in your file tree. once you have composite elements broken out, turn them into individual components and save them away to their associated folders. At this stage you should have a workable rough design that ready to be refined and finalized.
- Part two of the mastering process involves part by part cleanup and mastering. Open each of your saved parts and start checking it for proper dimensioning. remove unneeded elements that crept in during modeling, apply material properties, appearances, threads etc. Make sure you define holes and such if not already done. sometimes creating sketches and then recutting holes as needed. work to use whole number measurements where you can, machinists are lots happier when its a 5" measurement rather than 4.9984. Also make a point to properly orient and position your parts with relation to the origin. this will greatly simplify the drawing generation process. Don't start creating drawings or profiles yet, we need to make sure everything fits. Also add any other features at this stage such as logo cutouts, weight reduction holes, laser etches, bends, tabs or mortises etc. Also at this stage pay attention to components that are common or repeated multiple times. like for example table legs, don't create 6 different legs if they are all the same. create a master table leg and then in your master model you will create 6 duplicates of that one component. At this stage you may also want to consider turning on parametric modeling and reproduce the part fully parametric. this will allow for tracked changes and quick adjustments of different elements.
- if you have weldments or subassemblies start creating models of those, drawing in the various components used in their assembly, work from the simplest elements (ie create a weldment of the welded frame so that it can be used to build the components onto)
- NOTE. this note is a special one regarding hardware assemblies, to massively simplify large models that use a lot of the same nut bolt washer combos create subassemblies of these sets with individual identifiers so that you can just drop in the fully assembled connection instead to having to have 100 individual washers to position use your main models to work out the joints for these sets.
- Create a new model in your top folder called "[project Name]Master Model". Then start building your model. bring in each component and start bringing all your elements in and actual build your device. in this stage you will start using Joints to assemble components to one another. I tend to use the the bolt holes for bolted items and tabs and slots for positional; elements. once the major pieces are in place start on the secondary elements and finally the hardware. at this stage it is valuable to pay mare attention to the order of operations, clearances, hardware direction and access etc. make sure the motor will pass through the opening in the frame, will it fit if the pump is already installed or does the pump have to go in last. it may help to create some basic models of tools if this is something that may require frequent service this will help reduce ire and death threats from mechanics. Pay attention to alighnments and interferences. look for places where you may need to slot a hole to account for variations of aid in installation. look for places where a welded stud may be desired to aid in assembly and fastening. This stage is effectively a digital prototype. if done well, the first actual elements should go together with as minimum of fuss. This is also a great time to involve fabricators and end users to get their imput and impressions. if you're not sure about how something might fit ask them to look at it with you. they have different insights or may know of issues that you didn't think of(one time I failed to consider that a part weighed 800lbs and I didn't leave any way for a lifting tool to be attached as it was installed)
- Note at this stage it is again likely you may have to go back and refine some of your parts, tweak hole locations, switch out hardware etc, trust me it's worth the time. Another thing to keep in your head at this stage is to make sure you account for variability, try to incorporate elements that allow for compensating for variations in the components for example steel and aluminum plate can vary in thickness by as much as an eight of an inch. if you can design in the flexibility to accommodate such things.
- by the end of this stage you should have a pretty clean looking model and have nailed down most of the components its time to finalize everything. Figure out if you're going to use a parts identification system or just naming conventions etc. then start working through each part. finalize it, rename it(and record it in a table) generate drawings and illustrations, cast profiles or create solid models to send to machine shops etc. See notes below on part ID thoughts. By the end of this stage, your master model should have only properly named parts.
- Now you can start creating any master drawings of the model showing different views, calling out details etc. you can also generate sequential drawings showing order of assembly(different than using the animations) you can also use animations to create exploded parts diagrams with part lists.
- Ive personally found that the plug in BOMMER is outstanding for managing the bill of materials and allows you to enter a lot of detail with ease.
- at this point you should be able to start ordering parts. but don't go crazy, order a single set and build out a prototype unless your design is very simple. invariably something will creep in that would be an issue in the long run once the fabricators and mechanics have done their work and provided their feedback your ready to start your production.
Notes on Part IDs and naming conventions
there are literally no rules on how you should name your parts. it could be as simple as " part 1, 2, 3" or as complex as a 10 digit serial number/sku. I find it's good to adapt to the size of the project and the environment it is being made. For a simple home project I just call each thing what I think it would be called like "shelf" "shelf bracket, upper" "Mount" etc. for projects where you will be building multiples in a more formal environment especially where customers may be ordering parts, I prefer to create composite numbers that are reasonably easy to interpret. For huge models or corporate systems where thousands of parts are being managed a serial type numbering may be preferred I tend to dislike number codings for things but that's me. I like to be able to look at a part number and have a good idea where to find it and what it is in general rather than have to look everything up numerically
Here is how I like to do my part numbers;
[AA][BB][CC][XXX][D]
AA- Project identifier
BB- Sub Project identifier
CC- Element type(FP-Flat part, MP-Machined Part, SP-specialty Part, HW-Hardware, HA-Hardware assembly, WM-Weldment, SA-Subassembly, FD-Folded Part)
XXX-sequential id number
D-revision letter
It is also valuable for you to define what you will call different types of elements in your models. I tend to use these sorts of conventions;
- Plates- any element that is created from a flat sheet of material
- Bracket-any (generally) flat element that is positioned at an angle to a plate or set of plates to join them to each other can also apply to other elements that perform the same function
- Gussets- any (generally) flat element used to reinforce, or stiffen a connection or area of a flat part
- Fish plate - an element used to join two flat plates to create a larger flat plate
- Shaft- any element that spins and connects other parts
- Bar- a components that is used to connect things or to support things, tend to be uniform in crossecton and of a premaufactured nature
- Beam- generally a major structural element to which structural components or major assemblies or components are mounted(as distinguished from bars which tend to be smaller)
- Spacer- an element which is used to provide a standoff or extension of a mounting point. frequently these will have hardware passing through or into them or will be used to support other elements for positioning purposes
- Bushing- an element that surrounds another element to provide support to a connection or reinforce a structural element.
- Cover- something that acts to protect or shield a portion of a model, these are generally light duty and not structural in nature, not to be confused with guards or shields.
- Guards- these elements are generally robust structurally and intended to prevent interaction with elements of the machinery, access to pinch points, generally associated with safety of operation
- Shields- elements designed to protect the model from damage or interaction with outside elements can be heavy structures like skid plates or light elements like splash shields
- Tube- elements that have a hollow center and tend to have other things passing through the inside of them.
- conduit- a element used to route and protect wires
- Pipe- an element used to convey fluids or dense solids
- duct- an element used to direct flow of gasses or low density solids
- intake- an element into which things enter
- Exhaust- an element out of which things exit
- Snubber- an element used to absorb movement and facilitate alignment
- Strut- a longer element used to maintain alignment and position may allow for some degree of movement.
Sorry for the long winded response hope it helps someone even if to just put them to sleep.
