Introduction to Assemblies with Legos

Transcription

1 Introduction to Assemblies with Legos Basic Assembly Terminology Component: Individual Part of the assembly Align: Places both select surfaces/datums on the parallel or same side to an imaginary plane Two Aligned Surfaces Mate: Sets each selected surface/datum parallel with each other. Two Mated Surfaces: The Top of the 2x4_block and Bottom of the 2x8_flat Lego. The surfaces are touching each other Orient: Allows the user to align two surfaces and set an angle measure Center Axis/Insert: Aligning the Axis lines of two (2) holes, Hole and a Cylinder, or two (2) Cylindrical Objects. Offset: Defined distance for an Align or Mate Connection Creo Rigid Types of Assembly Connections Terms Normal: Is the default connection in Creo. This connection will rotate/move the part in order to constrain it in space. It does not typically place the part Mate/Align within the assembly; user should switch to Coincident or Distance in order to get the part to function in the desired way. Coincident: Align or Mate Connection that is a zero (0) offset. Distance: Offset user inputted value of an Align or Mate Connection Angle Offset: Set degree between two separate selected surfaces. Typically surfaces are parallel to a plane or each other; in an angle offset the user can input the desired rotation. Parallel: Parallel allows the user to select surfaces that are not touching or have a desired offset distance. The user can select two surfaces and declare them parallel; the surfaces do not need to be on the same plane.

2 Assembly Steps 1. Download Lego Parts From Class Website. Be sure to remove the Lego Parts from the.zip folder. DO NOT try to assemble parts while in a.zip file. You will be unable to save your assembly and may lose all of your work. 2. New > Assembly > Name: LegoAssembly 3. Tool Bar. All other Tabs are similar except for Model. Below is what the Model Tab looks like with important buttons pointed out. Manage Views and Appearance Gallery Assemble: Imports parts to make them part of the assembly. Drag Components: Allows user to grab components and see if they move apart from each other. Checks to see if parts are full constrained or can show movement for a mechanized assembly Modeling Features: I.E Extrude, Revolve, etc. Not recommended to modify parts within the assembly. Recommended to modify parts in their individual source file and let the software update the assembly file. 4. Model Tab > Select Assemble Icon > Navigate to the Lego Parts Folder > Select 2x4_Block.prt > Click Open Steps 1. Select Assemble 2. Navigate to Lego Parts 3. Select 2x4_Block 4. Select Open

3 The Component (2x4_Block Part) should appear on your screen in space. The component is Purple because there are not any constraints applied to it yet. 5. Component Control Bar User Defined: Allows user to adjust mechanized connections. We will leave it at default, which will eventually say Rigid. Software will try to predict the type of connection (Normal, Parallel, Coincident, Distance, etc. the user desires. If you know the connection you can preselect here or change it later Tracker Ball: Allows the user to move the part in space in the direction where there is no connections Placement Tab Shows all of the connections being made on the active component. User can edit/change connections status here. Status tells the user how connected the part is in the assembly. Be sure the status says Fully Constrained before Green Check out of the part assembly. NOTE: user can always Edit Definition on the part to edit the connections if needed later in the

4 6. Constraining the Component 1: 2x4_block We will first need to reorient the part so it is placed correctly on the page. Since this part is a polygonal solid model we will need three (3) constraints to lock the part into place. Essentially we need to constrain the part in the x, y, and z directions. Move the component using the Tracker Ball Away from the origin. a. Selection 1: Select the bottom of the block and the ASM_Top Datum. Select the Bottom of the component and the ASM_Top Datum b. The software will try to predict a connection of Normal. Change the connection from normal to coincident. This will make the ASM_Top Datum and Bottom of the part Aligned or flush with each other.

5 c. Next select the front surface of the component and the ASM_Front Datum. If a Distance connections appears either change it to coincident in the Placement Tab or enter a Distance of 0 Select Front Surface of Component and ASM_Front Datum. d. Last selection: select the Left Surface of the component and the ASM_Right Datum. This will place the component in the correct orientation and at the origin point. If a Distance connections appears either change it to coincident in the Placement Tab or enter a Distance of 0 Select the Left Surface of the Component and ASM_Right e. If the status reads Fully Constrained then Green Check the part out to complete the placement of this component. f. Turn the datums off. g. May Consider changing Color by Selecting the Part Name in the Model Tree and Clicking on Appearance Gallery Icon in the Model Tab. Select the desired color.

6 7. Adding a Second Component: 2x8_flat a. Model Tab > Assemble > 2x8_flat > Click Open b. First Constraint: first we will flip the part around so the bottom of the 2x8_flat is parallel with the top of the 2x4_block. Select the following Surface and make them Coincident. Rotate Part as needed to see the selection surfaces. Select the bottom of the 2x8_flat Select the top of the 2x4_block (Note: Do not select the top of the pegs on the 2x4_Block. We want these parts to snap together c. Place your part back into isometric d. Second Constraint: Select the following to surfaces to be offset aligned. Change Connection type to distance > enter a value of.3125 (Note may have to enter a if the part does not go the correct direction) Select the side surface of the 2x8_flat Select the Right Surface of the 2x4_block Change Connection type to distance with a value of.3125.

7 e. Third Constraint: Finally we will align the end of the 2x8_flat to the front surface of the 2x4_block. Select the following surfaces > set the connection to coincident. Select the end of the 2x8_flat Select the front surface of the 2x4_block f. Green Check if the Status is Fully Constrained g. Place part in isometric. Assembly should look as follows.

8 8. Adding a Third Component: 1x2_block_axle_holes a. Model Tab > Assemble > 1x2_block_axle_holes > Open b. First Constraint: Select the bottom surface of 1x2_block_axle_holes and the top of the 2x8_flat (Note do not select the top of the pegs) > Change Connection type to coincident c. Second Constraint: Select the following surfaces Front face of the 1x2_block_axle_holes and the side of the 2x8_flat change the following - Connection Type: Coincident - Select the Flip Icon in the Placement Tab (this will make the 1x2_block_axle_holes flush with the side of the 2x8_flat) d. Third Constraint: Select the following surfaces the Right side of the 1x2_block_axle_holes and the far end from the 2x4_block of the 2x8_flat. Place a 0 value is distance comes up or change the connection type to coincident. e. Green Check if Status is Fully Constrained f. Place assembly as an Isometric

9 g. The Part should look as follows 9. Fourth Component: Pin/Axle In a pin/axle connection the software only requires two (2) constraints to lock the part in place. The first constraint being the alignment of the axis line of the pin/axle and the axis line of a hole the pin/axle will be inserted into. a. Model Tab > Assemble Icon > Axle > Open b. Constrain 1: Inserting the pin/axle into a hole. Connection Type should be Coincident Option 1: Select the Cylindrical Face of the axle and the interior Cylindrical Face of the hole on the 1x2_block_axle_holes part > change connection type to coincident Option 2: Turn on the Datums and select the Axis Line for the Axle and the Axis Line for the Hole of the 1x2_block_axle_holes part > change connection type to coincident Option 1 Option 2 OR

10 c. Constraint 2: Select the end of the Axle and the Right Face of the 1x2_block_axle_holes > Set Connection Type to Distance > Value of 1 d. Green Check if Status is Fully Constrained e. Assembly should look as follows

11 10. Component 5: Angled 1x4_block_axle_holes Here we will place a component that will have an offset angled off a given component of the assembly (2x4_block). For this component we will have three (3) constraints even though we are using a pin/axle and a hole because we want to lock the angle of the Angled 1x4_block_axle_holes into place based on the orientation of another block. a. Model Tab > Assemble Icon > 1x4_block_axle_holes > Open b. Constraint 1: Select the Cylindrical inside of the middle hole on the 1x4_block_axle_holes and the Cylindrical Face of the Axle to line the hole up > Make sure the connection is a coincident c. Constraint 2: Select the left face of the 1x4_block_axle_holes and the end of the Axle > Be sure the connection is a coicident

12 d. Constraint 3: Angle Offset Select the Front Face of the 1x4_block_axle_holes and the Front face of the 2x4_block > Change the connection type to Angle Offset > Value of 135 e. Green Check if the Status is Fully Constrained.

13 f. Final Part should look as follows 11. Check Connections. a. Model Tab > Select Drag Components > Left Click on any of your parts and try and drag them away. Result Parts DO NOT Move: The Assembly is fully constrained Parts DO Move: Parts are not full constrained and you must edit definition on the parts that moved and add/fix the constraints on the component. 12. Add at least two more parts onto this assemble. BE SURE that the parts are Fully Constrained. Show Mr. Jourden upon completion 13. Showing all a components features (datums, extrudes, holes, etc) a. Select the Tools option from the Model Tree > Select Tree Filters b. Check the Features and Suppressed Features Icons c. Click Close d. Notice on the model tree that there are drop down arrows next to each part. This allows you to see the how the components were created. The user can even edit the definition any of these features of the parts within the assembly. This is not always recommended or can be easy to see within a the assembly e. The user can also Select datums or other features and right click on them to hide the selected item. Datums are the usual use for this since the assembly can get complicated to look at with each parts datums show up when datums are turned on. f. Try hiding the ASM_Front, ASM_Top, and ASM_Right Datums by selecting them > right click > Hide Notice the datums disappear when datums are turned on. May unhide them by right clicking on the ghosted datum > Select UnHide

14 Assignment: Design something using at a minimum 15 Legos. NOTE: you may use the same Lego piece more than once in your design. You may build more Lego parts if desired. Feel free to add or change colors of your pieces as well (If new Lego parts are design please let Mr. Jourden know so he can add the files to the Lego Library.) Final Submission: 1. Place your finished design as an Isometric centered on your Border and Title Block. Keep your Isometric with the colors. 2. Fill out Border and Title Block 3. Place the name of the part in large letters above your below your isometric (like a title) 4. On the Border and Title Block create a list of the parts you used and the quantity. See Mr. Jourden on how to create a table in Creo. 5. Print the Final Drawing on the B Color Printer (you may make a second print for yourself if you like) 6. See Mr. Jourden for mounting your drawing on matte board.