Basic Part Design Tutorial/it: Difference between revisions

From FreeCAD Documentation
(Created page with "A questo punto si dovrebbe avere un disegno completamente vincolato, come indicato dal cambio di colore e dal messaggio mostrato nella Vista Combinata. Lo schizzo dovrebbe app...")
(Created page with "Il video dei passaggi utilizzati in questa parte del tutorial è in: https://youtu.be/cUyPnCMeTgg")
Line 46: Line 46:
Now in the Combo View, click on the Close button to leave the sketch edit mode and select [[File:PartDesign Pad.png|32px]] Pad from the toolbar or from the Part Design menu. This will give you a Pad dialog in the Combo View. Using that dialog, first using the Type pulldown menu, select Two dimensions. Drawing presented at the beginning of this tutorial says the part is 53 mm long. We do it by Padding our sketch both ways from the center plane to make up that distance i.e. make the pad symmetric in relation of sketch-plane. The reason for is seen later when creating features. For now, given we want it to be 53 mm long in total we will input 26.5 for Length, and 26.5 again for the Second length. Alternatively, you can provide a single length of 53 mm and click the Symmetric to plane check box. Once that is done we now have our base solid upon which we will add additional features to construct our part.
Now in the Combo View, click on the Close button to leave the sketch edit mode and select [[File:PartDesign Pad.png|32px]] Pad from the toolbar or from the Part Design menu. This will give you a Pad dialog in the Combo View. Using that dialog, first using the Type pulldown menu, select Two dimensions. Drawing presented at the beginning of this tutorial says the part is 53 mm long. We do it by Padding our sketch both ways from the center plane to make up that distance i.e. make the pad symmetric in relation of sketch-plane. The reason for is seen later when creating features. For now, given we want it to be 53 mm long in total we will input 26.5 for Length, and 26.5 again for the Second length. Alternatively, you can provide a single length of 53 mm and click the Symmetric to plane check box. Once that is done we now have our base solid upon which we will add additional features to construct our part.


A video of the steps used in this portion of the tutorial is here:
Il video dei passaggi utilizzati in questa parte del tutorial è in:
https://youtu.be/cUyPnCMeTgg
https://youtu.be/cUyPnCMeTgg



Revision as of 20:31, 13 April 2018

Tutorial
Argomento
Modellazione
Livello di difficoltà
Base
Tempo di esecuzione
Circa un'ora
Autori
HarryGeier (HarryGeier)
Versione di FreeCAD
0.17 o superiore
Files di esempio
Basic Part Design for v0.17
Vedere anche
Nessuno

Questo tutorial presenta ai nuovi utenti alcuni degli strumenti e delle tecniche utilizzate nell'ambiente Part Design v0.17. Questo tutorial non è una guida completa ed esaustiva all'ambiente Part Design, molti strumenti e molte capacità non sono utilizzate. Questo tutorial guida l'utente attraverso i passi necessari per modellare la parte mostrata nell'immagine sottostante utilizzando degli schizzi.

Questo tutorial è basato sul tutorial Basi di Part Design di Quick61 con gli aggiornamenti per la versione 0.17.

Un video dell'intera costruzione è disponibile in: https://youtu.be/geIrH1cOCzc

( sotto è riportata una schermata di ogni sezione )

Prima di iniziare

Lo scopo

In questa esercitazione, si prevede di utilizzare l'ambiente Part Design per creare un modello solido 3D della parte mostrata nel Disegno sottostante. Tutte le dimensioni necessarie per portare a termine questo compito sono date. Si inizierà creando il nucleo della forma da uno schizzo di base e poi si costruirà sulla forma aggiungendo ad essa ciò che è conosciuto come caratteristiche (Features). Le caratteristiche aggiungono del materiale, o rimuovono del materiale dal pieno mediante l'uso di disegni supplementari accompagnati dalle operazioni delle funzioni. Questo tutorial non utilizza tutte le funzioni e gli strumenti disponibili nell'ambiente Part Design, ma dovrebbe utilizzarne abbastanza per dare agli utenti di questo tutorial le basi su cui costruire le loro conoscenze e competenze.

La Parte

Costruzione della Parte

Inizio

Prima di iniziare accertarsi di essere nell'ambiente Part Design. Fatto questo, creare un nuovo documento, se non è ancora stato fatto. Dato che salvare spesso il proprio lavoro è una buona abitudine, per prima cosa salvare il documento dandogli il nome preferito.

Ogni lavoro in Part Design inizia con un Corpo. Fare clic su questo pulsante per creare e attivare un nuovo contenitore Corpo Il corpo conterrà almeno uno Solido . Qui lo creiamo da uno Schizzo . Fare clic su questo pulsante per creare un nuovo schizzo all'interno del corpo appena creato. Il primo schizzo si basa su un piano di Origine del corpo. Scegliere il piano YZ

This switches the 3D Window into the Sketcher mode

Per procedere, utilizzare lo strumento Polilinea e fare una forma simile a quella dell'immagine successiva. Non è necessario che sia perfetta, in quanto, dopo averla costruita, si applicheranno i vincoli. Dopo aver prodotto la forma di base, si passa ad applicare i vincoli. Se la casella Autovincoli era impostata su ON, alcuni di loro saranno già stati applicati automaticamente, in caso contrario, procedere come segue.

  1. Selezionare le due linee orizzontali con il mouse facendo clic su di esse e, una volta selezionato, fare clic su vincolo orizzontale.
  2. Selezionare la linea verticale sulla destra e poi cliccare su vincolo verticale.
  3. Selezionare i punti di inizio e fine della polilinea e poi fare clic su vincolo coincidente per chiudere la polilinea.
  4. Selezionare la linea orizzontale inferiore e la linea verticale destra e applicare un vincolo uguaglianza.
  5. Selezionare entrambe le linee orizzontali o verticali e applicare un corrispondente vincolo di lunghezza orizzontale o verticale e dargli un valore di 26 mm.
  6. Selezionare la linea orizzontale superiore e applicare il vincolo di lunghezza orizzontale e assegnargli il valore di 5 mm
  7. Seleziona il punto in basso a destra, (vertice) della linea orizzontale Origine e poi il punto centrale della griglia e applicare il vincolo di coincidenza per bloccare la forma.

A questo punto si dovrebbe avere un disegno completamente vincolato, come indicato dal cambio di colore e dal messaggio mostrato nella Vista Combinata. Lo schizzo dovrebbe apparire esattamente come nell'immagine sottostante.

File:Tut17 profile.png

Now in the Combo View, click on the Close button to leave the sketch edit mode and select Pad from the toolbar or from the Part Design menu. This will give you a Pad dialog in the Combo View. Using that dialog, first using the Type pulldown menu, select Two dimensions. Drawing presented at the beginning of this tutorial says the part is 53 mm long. We do it by Padding our sketch both ways from the center plane to make up that distance i.e. make the pad symmetric in relation of sketch-plane. The reason for is seen later when creating features. For now, given we want it to be 53 mm long in total we will input 26.5 for Length, and 26.5 again for the Second length. Alternatively, you can provide a single length of 53 mm and click the Symmetric to plane check box. Once that is done we now have our base solid upon which we will add additional features to construct our part.

Il video dei passaggi utilizzati in questa parte del tutorial è in: https://youtu.be/cUyPnCMeTgg

Features with pocket and external geometry

Using the mouse or the view icons turn the model around so you can see its back. Once the back of the part is visible, select the back face by clicking on it as seen in the next image.

After the face is selected, click on the New sketch icon in the toolbar or from the Part Design menu and that will map our next sketch to the back face of the part. Now select rectangle tool and place a rectangle on the rear face of the part in a similar fashion as shown below. Now following the steps listed, constrain the sketch.

  1. Select one of the horizontal lines apply a horizontal distance constraint and a value of 5 mm.
  2. Select one of the vertical lines and give it a vertical distance constraint and a value of 11 mm.
  3. Use External geometry tool and select the upper right vertex of the face and click it so you are provided a point from the external geometry to link our sketch to.

Select that point you just made available with the External geometry tool and then select the upper right vertex of the rectangle and click on the coincident constraint. At this point the sketch should be fully constrained and look like the next image.

Once that is done, click the Close button at the top of the Tasks tab in the Combo View window, then select Pocket tool from the toolbar or Part Design menu. Using this tool is the opposite of the Pad tool. As the Pad tool adds material to the part, the Pocket tool removes material from the part. Both operations are called features. In this Pocket operation we want to select Through all from the type pulldown-menu and then click the OK button.

For the next operation, make sure that “Pocket” is selected in the Model tree view and once done, click on the Mirror feature on the toolbar or from the Part Design menu. In the Mirror dialog in the Combo View, select Horizontal sketch axis from the Plane pulldown menu. Then click OK. The Mirror feature works in this way because the base feature of our model was Padded both ways from the horizontal plane in the first operation with the base sketch. If all has gone well, you should now have a part that looks like the image below after you orbit it around to the front.





A video of the steps used in this portion of the tutorial is here: https://youtu.be/wiGXV9G7mrM


Features with pad and external geometry

After taking a look, orbit back around and once again select the back face of the part and select that face to map the next sketch to.

Select New sketch and make a new rectangle in the manner similar to what is shown below in the next image. Then proceed to add dimensional constraints to the rectangle.

  1. Select a horizontal line and apply a horizontal distance constraint with a value of 16.7.
  2. Select a vertical line and apply a vertical distance constraint of 7 mm
  3. Using the External geometry tool, select the upper left vertex of the part face.

Now selecting the upper left vertex of the rectangle and the external geometry point, click on the coincident constraint to fully constrain the sketch.

Next we will click on the Pad feature and in the Pad dialog in the Combo View we want a length of 26 mm leaving the type as Dimension and then placing a check on the Reversed checkbox. Using the Reversed checkbox will cause the Pad to go into the part instead of away from the part. This operation provides with the following result.

Once again use the Mirror feature to get the second pad. First ensure that created Pad is selected in the tree view, then click on Mirror in the toolbar of select it from the Part Design menu. We will repeat the operation we did for Pocket above and select Horizontal sketch axis from the Plane pulldown menu.

A video of the steps used in this portion of the tutorial is here: https://youtu.be/Ido1owp8ubc


Feature with pocket and external geometry

At this point orbiting the part around to the front, we can see that our part is now starting to look like the part in the dimensioned drawing at the beginning of this tutorial. Once you have the view of the front, click on the sloped face with your mouse to select the face we will use for the next sketch.

Here we will use the rectangle tool and place a rectangle in our sketch and once having done so, apply the following constraints.

  1. Select a horizontal line and a vertical line, and after both are selected, click on the Equals constraint.
  2. Select either a horizontal or vertical line and apply a corresponding horizontal or vertical distance constraint with a value of 17 mm
  3. Using the External geometry tool, select the top right vertex as shown in the image below.

Now using the dimensions from the drawing, apply the following constraints.

  1. Select the external geometry point and the upper right vertex of the now square sketch and apply a horizontal distance constraint of 7 mm
  2. Select the external geometry point and the upper right vertex of the now square sketch and apply a vertical distance constraint of 11 mm

The result should be as follows.

At this point if we were to simply Pocket this sketch, the resulting hole would be perpendicular to the sloped face that it is mapped to, and this is not what we want.


We want the hole to be perpendicular to the back face, but it's projected dimensions are not the 17 mm x 17 mm dimensions that are given in the drawing. Now we could do the math and calculate the dimensions needed, or we can use the tools provided in FreeCAD to make that projection for us.

A video of the steps used in this portion of the tutorial is here: https://youtu.be/x4d5nZPWCLQ


To create pocket which has the sloped rectangle as it´s outlet, we draw a new rectangle on the rear side, using the projection of the sloped rectangle as an external reference. Orbit the Solid around to see the rear face of the part once again and select the back face to map the final sketch to.

Select New sketch from the toolbar or Part Design menu. Now in sketch edit mode, we do not see the Sketched rectangle of the slope. To make it selectable , we switch the combo view to model tab and select the last sketch made (Sketch003) on the sloped plane. Then using the spacebar, make it visible. Next, select the mirror feature above (mirrored001) and again using spacebar, hide it. Ten you should see the rectangle inside the 3D View. You may continue to work with the model tab visible, or switch back to tasks tab. Using the External geometry tool, select the connected horizontal and vertical edges of the sloped rectangle.

  1. Select the upper left vertex of the rectangle and the upper left point of the external geometry and click on the coincident constraint.
  2. Click on the lower right vertex of the rectangle and the lower right point of the external geometry and click on the coincident constraint.

And we should end up with this.

For the final step in this tutorial, close the sketcher window using close or fish editing from the context menu of sketch004 and then select the Pocket feature from the toolbar or from the Part Design menu. From the Type pulldown select Through all and click the OK button.

At this point, you will see some lines which come from intersecting features. In this case the side block intersects with the base profile letting it appear as a triangular block above the profile. To remove these lines, you can either switch on "refine shape" in your Part Design Settings or , to save some processing speed and still have these lines while constructing, individually switch it on at each feature, which will create such lines. The Setting on feature level can be done in the "data" tab of the feature. Set the refine property to TRUE to invoke refining.




A video of these steps of the tutorial is here: https://youtu.be/UYI0gvxCYeI


This tutorial and your model are complete.

Risorse aggiuntive

  • Links to accompanying video have been included.
  • FreeCAD file for comparison (made with 0.17) Download