Cartesian Tube Profiling
3D Modeling Guidelines
March 2013
Table of Contents
3
Design Checklist
3
Request for Quote: Checklist
4
Inquiry Documents
5
Preparing SolidWorks for Modeling
6
Weldment Modeling: Step-by-Step Instructions
10
Weldment Modeling: Cutlist Setup
13
Using other CAD packages: Best Practices
14
Bending: Information and Guidelines
15
Bending: Die Chart
16
Weldment Design: Square Tubes
17
Weldment Design: Trimming Options and Guidelines
18
Weldment Design: Special Design Considerations
20
SAE Student Projects
- pg 2 of 21 -
Design Checklist
- pg 3 of 21 -
Review this checklist and ensure that your design follows the guidelines to ensure an accurate and timely quote and tube
kit. The requirements listed are explained in detail in the following pages.
1. Weldment profiles need to match the material. Ensure wall thickness offset are correct, and geometry is accurate
and For square tubes, ensure that corner radii are correct.
2. Ensure that all individual parts have a unique tube number in your cutlist. Match the part number to the balloon
number when possible.
3. Please ensure that your assembly drawing is legible. Balloon lines should not cross, and need to be able to read
clearly. Please avoid the use of Auto-Balloon functions.
4. Use the provided Sample Material List as a basis for your tube kit material list to ensure that you include Quantity, Outside Dimension, Wall Thickness, tube type, approximate length, and any mid part features (holes, slots or
bends).
5. Confirm that all nodes are trimmed correctly and in the order to be manufactured. Check that there are no hollow
nodes or extended trims.
6. Our process takes the profile path directly from your model. So the cut part is entirely dependant on the accuracy
of the 3D data provided to us. Ensure that each tube is included, and modeled correctly (tube size, wall thickness,
etc in model matches design intent).
7. All bent tubes must follow our bend constraints: bend radii for a given wall thickness, distance from bend to end
of part, distance between bends, bend profile tangency.
8. If using a 3D model software other than SolidWorks, your neutral format files are exported as solid bodies, NOT
surface bodies.
9. Square tube require a minimum of 0.010” offset from the inside face for profiles.
Request for Quote: Checklist
In order to provide an accurate and timely quote, we require a specific set of information about your project or design. If
you do not currently have a 3D model, we are able to provide technical support. Please see our Services page.
1.
•
•
•
2.
3.
Send pdf of ISO weldment drawing with balloons.
Material List (with all required tube information).
Entire model (Weldment)
We review model: Trims, formed tubes, etc and provide quote.
Once the model is approved: Send individual 001.sldprt files (numbered per balloon and BOM)
The files are described in detail in the following sections.
Inquiry Documents
- pg 4 of 21 -
In order to provide an accurate and timely quote, we require a specific set of information about your project or design. If
you do not currently have a 3D model, we are able to provide technical support. Please see the Services page on our website.
The information relies on two key aspects, an overall assembly drawing of the tube structure and the material list. This information clearly and quickly defines the scope of supply, primary features and part numbers, and also allows us to quickly
and easily submit a proposal.
1. Material List noting each part in the weldment assembly
• This document should match the cutlist produced and supplied in the assembly drawing.
• The following information needs to be supplied
for each part: Quantity, Outside Dimension,
Wall thickness, tube type, approximate length,
and any additional features.
• Please use the BOM template file supplied in
the Reference Document section of the website.
• This document is mandatory for us to create an
accurate and timely quote.
2. Assembly drawing with the cutlist/material list
ITEM NO. PARTNUMBER QTY.
Description
11
011
1
Tube 1.000 x 0.065
12
012
1
Tube 1.000 x 0.065
13
013
1
Tube 1.000 x 0.065
14
014
1
Tube 1.000 x 0.065
15
015
1
Tube 1.000 x 0.095
LENGTH
12
• This drawing requires balloons that clearly
indicate each member of the weldment and is
referenced by the Bill of Materials.
15
14.08
68
14.08
54.597
16
016
1
Tube 1.000 x 0.095
14
17
017
1
Tube 1.000 x 0.095
100.814
18
018
1
Tube 1.000 x 0.095
20
19
019
1
Tube 1.000 x 0.049
14.883
20
020
1
Tube 1.000 x 0.049
17.383
21
021
1
Tube 1.000 x 0.049
10.078
22
022
1
Tube 1.000 x 0.049
10.078
23
023
1
Tube 1.000 x 0.065
28.018
DISCLAIMER: MODEL AND DRAWING ARE FOR DISCUSSION/ TEACHING
PURPOSES ONLY. THE MODEL DOES NOT COMPLY WITH SAE RULES &
REGULATIONS. IT HAS BEEN MADE AVAILABLE STRICTLY AS A TEACHING
TOOL.
17
67
24
024
1
Tube 1.000 x 0.065
28.018
25
025
1
Tube 1.000 x 0.049
28.638
26
026
1
Tube 1.000 x 0.049
28.638
60
20
27
027
1
Tube 1.000 x 0.065
32.213
28
028
1
Tube 1.000 x 0.065
32.213
36
38
29
029
1
Tube 1.000 x 0.065
34.665
30
030
1
Tube 1.000 x 0.065
34.665
31
031
1
Tube 1.000 x 0.065
30.599
64
32
032
1
Tube 1.000 x 0.065
30.599
33
033
1
Tube 1.000 x 0.049
3
34
034
1
Tube 1.000 x 0.049
3
• Each part requires a unique part number and
will be used to ensure part numbers and model
match the specifications supplied. Mirror parts
are not identical.
22
32
34
66
63
19
62
35
035
1
Tube 1.000 x 0.049
12.885
36
036
1
Tube 1.000 x 0.049
12.885
37
037
1
Tube 1.000 x 0.049
15.187
30
38
038
1
39
Tube 1.000 x 0.049
15.187
Tube 1.000 x 0.049
34.382
40
040
1
Tube 1.000 x 0.049
34.382
41
041
1
Tube 1.000 x 0.049
11.75
42
039
042
1
1
Tube 1.000 x 0.049
19.898
58
21
56
43
043
1
Tube 1.000 x 0.049
10.301
44
044
1
Tube 1.000 x 0.049
10.301
45
045
1
Tube 1.000 x 0.049
14
54
15
46
046
1
Tube 1.000 x 0.049
14
47
047
1
Tube 1.000 x 0.049
14.242
28
18
74
69
48
048
1
Tube 1.000 x 0.049
14.242
49
049
1
Tube 1.000 x 0.049
16.923
50
050
1
Tube 1.000 x 0.049
16.923
71
65
51
051
1
Tube 1.000 x 0.049
20.312
52
052
1
Tube 1.000 x 0.049
20.312
53
053
1
Tube 1.000 x 0.049
20.024
46
• Create this drawing from the 3D model, save as
a PDF file. Please send us the PDF file version
only.
37
26
31
33
54
054
1
Tube 1.000 x 0.049
20.024
55
055
1
Tube 1.000 x 0.049
19.069
50
59
56
056
1
Tube 1.000 x 0.049
19.069
57
057
1
Tube 1.000 x 0.049
21.341
58
058
1
Tube 1.000 x 0.049
21.341
70
35
44
42
59
059
1
Tube 1.000 x 0.049
9.047
60
060
1
Tube 1.000 x 0.049
9.047
61
061
1
Tube 1.000 x 0.049
18.456
62
062
1
Tube 1.000 x 0.049
18.456
63
063
1
Tube 1.000 x 0.049
15.548
61
40
12
29
64
064
1
Tube 1.000 x 0.049
15.548
65
065
1
Tube 1.000 x 0.049
17.427
66
066
1
Tube 1.000 x 0.049
17.427
57
55
14
67
067
1
Tube 1.000 x 0.049
36.978
68
068
1
Tube 1.000 x 0.049
36.978
69
069
1
Tube 0.875 x 0.049
30.195
70
070
1
71
Tube 0.875 x 0.049
19.285
Tube 0.875 x 0.049
10.909
72
072
1
Tube 0.875 x 0.049
34.971
73
073
1
Tube 0.875 x 0.049
20.8
74
071
074
1
1
Tube 0.875 x 0.049
14.171
27
53
73
24
51
72
16
45
49
25
23
REV'N
DATE
DRAWN APPRVD. DESCRIPTION
43
UNIVERSITY OF ABC
47
41
11
39
SPRINGFIELD, SOMEWHERE, USA
THIS DRAWING OR THE INFORMATION CONTAINED HEREIN MAY NOT BE REPRODUCED
WITHOUT PERMISSION FROM UNIVERSITY OF ABC
• See an example of an appropriate assembly
drawing in the Reference Document section of
the website.
13
LINE1
LINE2
LINE3
DRAWN: INIT
'C' SCALE: 1:5
DATE: XXX
PROJECT NO.
DRAWING NO.
PROJECT
DRAWING
REV NO.
X
3. 3D Solid body model of the tube structure with properly defined geometry
• In the quoting process, this model is primarily
used to double check that bending standards
and geometry have been properly defined.
• This is to be supplied in addition to the two
documents above and does not replace them.
In order to receive a accurate and quick quote,
we require the two documents listed above
and will use the solid body model to ensure
that all specifications and constraints are met.
Preparing SolidWorks for Modeling
- pg 5 of 21 -
SoldidWorks is a very useful program for design tube kits and weldments. Spending time to setup the program to be optimized for weldments will reduce the amount of time required to produce the information needed for quoting.
Weldment Setup: Properties File
The Weldment properties file is a text file which determines what options will be
available in the dropdown menu for a cutlist item. This information is used when
creating automatic cutlists
1. Find your weldment properties file > Tools\System Options Tab\File Locations\Show Folders for: Weldment Property (This will show the folder in
which your weldmentproperties.txt file should be located. Typically will be in
C:\SolidWorks Data\lang\English)
2. If there is no folder shown, then you will need to add a location and create
your own weldmentproperties.txt file
3. Go to this location and open the text file. It should have the same content
and format as the side bar to the right.
Weldment Profiles: Creating Library Feature Parts (.sldlfp)
1. Create a new part in SolidWorks.
2. Create a sketch on the front plane.
3. Sketch: Create the Outer Diameter (OD) of the tube. Offset
the OD inward by the wall thickness. Ensure that you offset
inward, as the inside radius is not equal to the outside
radius.
4. Save File
5. File\Save As..
6. File name: 1.000 x 0.035
7. Save as type: Lib Feat Part (*.sldlfp)
8. Description: 1.000 x 0.035
9. Repeat steps above to complete your weldment profile
library
Weldment Profiles: Selection and Use
We have a large selection of
Chromoly 4130N in stock. We
recommend using round tubing
because it is more readily available and significantly cheaper.
Sometimes square tubing is
required. To insure that the
tubes are modeled as accurately
as possible, here are the profiles
which must be followed when
doing square tubes.
SQUARE TUBES
DIM A
THICKNESS
OUTSIDE
RADIUS
0.750
0.035
0.066
0.750
0.049
0.093
0.750
0.058
0.110
0.750
0.065
0.125
1.000
0.035
0.066
1.000
0.049
0.093
1.000
0.058
0.116
1.000
0.065
0.123
weldmentproperties.txt
DESCRIPTION
PARTNUMBER
REVISION
MATERIAL
WEIGHT
LENGTH
COST
SOURCE
SW-Part Number
Weldment Modeling: Step-by-Step Instructions
- pg 6 of 21 -
The 3D model, drawings, material lists and design must be well organized and properly presented. Anyone can create a 3D
model ‘cartoon’. It takes additional time and effort to properly prepare, design, organize and present this information for us
to efficiently manufacture the components.
• Our main concern is generally regarding the tubes with bends. The bends must be modeled with centerline bend radii
that match our dies and some other basic constraints.
• Ensure all trims are complete, especially at multi-tube clusters.
• Ensure left side and right side parts are assigned separate part numbers. Do not mirror parts! Mirrored profiled tubes do
not have identical tool paths.
• Ensure the tubes are modeled as continuous solid bodies. Not surfaces or splined curves. All segments of a curved tube
must be modeled correctly. Do not use fixed points.
The SolidWorks weldment, part drawing and bill of materials shown below has been provided as a sample on our website.
For further details and to follow along with the steps, please download and review. Sample files link.
Weldment Modeling Procedure
This guide is to assist designers in preparing information suitable for our tube profiling process. These methods and suggestions are specifically for SolidWorks but should be applicable to other 3D cad packages.
Tubing structures are best suited to be built as a ‘weldment’ part. Some advantages are:
• one file contains the complete parametric information and therefore can be sent without related attachment files or
libraries
• trim and extend features are quick and easy
• profile library of tube sizes is convenient for creating a more ‘automatic’ BOM
• one file to update with any changes to tube sizes or geometry
Before starting your modeling; make sure that you have your weldment library updated and your weldment file in the
correct location. See Weldment Profiles: Selection and Use on the previous page.
Profile sketch on the initial reference plane of the structure.
1. Each structure starts by establishing an initial reference plane. This plane is usually through the centerline of the
structure. This establishes the profile of the structure. This is typically a 2D sketch. Avoid using 3D sketches.
2. Create a 3D wire frame representing the tube centerlines of the major structural tubes ensuring the parametric
features are fully defined as the structure grows.
- pg 7 of 21 -
Formed tubes are defined in unique sketches and reference the initial 2D profile sketch.
3. Define formed tubes in unique sketches/planes.
4. Build the tube structure on the solid model generally in the same order as one would build the structure on the shop
floor.
Additional tube centerlines are added to grow the structure.
5. Add the tubes as ‘Structural Members’ with the correct OD and wall thickness. Do not combine lines and paths into one
solid body until the structure is complete. Do not ‘merge arc segment bodies’ when creating bent tubes. The trimming
features are generally more reliable when the bodies are not combined.
6. Use ‘Trim/extend’ to trim each tube as it is added to the existing structure. This is less confusing than determining the
trim sequence with all tubes left untrimmed in the structure. See General Trimming Procedure for more information.
7. Ensure the parametric design features and geometry are fully defined as you proceed (fully define sketches; no sketches with(-) after the sketch name) .
8. Avoid ‘mirroring’ tubes. Mirrored tubes generally have unique profile paths and require separate profile programs to
produce. Trim features are more robust. Changes are easier to apply downstream.
- pg 8 of 21 -
Structural Members are added and trimmed in the order that the structure is to be built on the shop floor.
Complete chassis with main, formed and supporting tubes as structural members.
9. Once all the tubes in the solid model are added and trimmed, combine the bent tube segments as required to produce
single tube components.
10. Assign each tube in the solid model a unique part number. A detailed description of how to properly setup the Cutlist
in SolidWorks is given in the Cutlist Setup section of this document. Please follow these instructions before continuing.
11. Create a drawing with the 3 main views (side, front, top) plus any important section views. Add overall dimensions,
station dimensions and layout dimensions to verify the design configuration. These dimensions will also be required to
assemble and build the tube structure on the weld table.
12. Review and check the design:
• confirm the design dimensions with your drawing
• confirm tube sizes
• confirm all tubes are shown
• review all trims at tube clusters
13. Confirm that bend radii and tube sizes are compatible with available bending dies and manufacturing procedures.
Please see Bending: Information and Guidelines and Bending: Bend Die Chart for further information.
- pg 9 of 21 14. For Cartesian to verify your model, we need to see either the entire model (if done in SolidWorks) or a sampling of the
model (all bent and square tubes, a small sample of straight tubes) to check that the model meets the requirements
and is programmable.
15. Once the model has been approved by Cartesian, produce a part file for each tube in the weldment maintaining the
parametric link to the solid model weldment. This is achieved by opening all of the cutlist folders and right clicking on
the bodies and ‘Insert into New Part’.
16. Visually inspect each tube when saving. Check the end trims. Save this file in its native (.sldprt) format. Save the part as
its’ 3-digit body number. If you are using a CAD program other than SolidWorks, please see the ‘Using other CAD packages’ section.
17. Some tubes may require additional steps before saving:
Tubes with Bends:
• ensure formed tubes are a single body, by combining sections at the end of the model
• Please review bend features with us prior to approving the final design to ensure compatibility with bend dies
and manufacturing procedures.
Square tubes:
• verify radii and offset requirements for the square tubes cross section.
18. Send the files required for quotation. The are listed in the Request for Quote checklist.
19. From this file we can extract the profile data and generate the CNC tool path for the tube profiler.
20. We will profile, label, package and send a set of tubes ready for weld assembly
Notes:
Feathered faces: Our tube profiling process always cuts the tube perpendicular to the tube surface. Our programming path
will eliminate the ‘feathered’ edges which result from 3D modelling. This perpendicular cut to the surface is ideal for welding and results in a complete tube to tube contact around the perimeter.
Weldment Modeling: Cutlist Setup
- pg 10 of 21 -
When you have completed your model, you will have all of your bodies in your Cut list() folder at the top of your design
tree. They will be named after their structural member or the last feature which affected them. Notice that the number of
bodies will be shown in brackets after the ‘Cut list’ title.
1. Right click on the Cutlist(XX) folder. ‘Automatic’ will likely be checked. We want to turn off ‘Automatic’, so click ‘Automatic’ again and this will toggle off the check mark.
2. Now rename all of your bodies to be 3-digit numbers in successive order; give a different number to all parts even if
you think they are identical. We start with 011 and move onward. You can start at any number you wish, just make
sure there are no missing numbers. We also try to pair left hand parts with right hand parts or bottom parts with top
parts. However, this is not a requirement.
3. Right click on the Cutlist(XX) folder and select ‘Update’. This will place all of the bodies in individual cutlist item
folders. Some folders may have more than one part in them. This is an indication that the parts are identical. But we
would prefer that all of the parts have their own number and cutlist item folder, so delete the folders which have multiple bodies in them. When you delete the folder, Solidworks will place the body at the bottom of the cutlist.
4. All of the bodies require a cutlist item folder. Go to the bottom of the cutlist folder and right click on the individual
bodies and ‘Create Cut List Item’. This will place the body in a cut list item folder. (You cannot ‘Create Cut List Item’ if
you have ‘Automatic’ still on).
5. Adding a property to cutlist folders: open all of the Cut List Item folders so the bodies can be seen. Right click on a
Cut-List-ItemX() folder and click ‘properties’. This will bring up a ‘Cut-List Properties’ window. Select a new property
cell line and click the dropdown menu under ‘Property Name’ column. If your weldment property file is correctly
placed, you will get a choice of options: choose ‘PARTNUMBER’. Enter the value 3-digit body number. Repeat for all of
the tubes. The model is now complete. (Note: your ‘description’ field will be filled with the tube size if you had set up
your weldment library correctly).
- pg 11 of 21 -
6. Open or create your model drawing. Put an isometric view of the model in on a sheet. Insert your weldment BOM:
Insert\Tables\ Weldment Cut List. Select the isometric and decide on what number you would like your table to start at
(depending on how you numbered your bodies). Click anywhere on the screen to insert the table.
7. Add a ‘PARTNUMBER’ column: Right click anywhere on the table and insert\Column Right (or Left). Click the top of the
column to see its’ properties. Change the column to a ‘Cut list item property’, then select the Custom property of ‘PARTNUMBER’. Now all of your partnumbers will appear in the column. Right click at the top of the column and sort\ascending. Check that all of your numbers line up with the balloon numbers. Forgot a number?! Go to the model and change
the highest number to the missing number and update its’ property cutlist item to the new number. Resort your table,
check and repeat if necessary.
8. Now use the balloon function in Solidworks to identify each part.
ITEM NO. PARTNUMBER QTY.
Description
LENGTH
11
011
1
Tube 1.000 x 0.065
12
012
1
Tube 1.000 x 0.065
15
13
013
1
Tube 1.000 x 0.065
14.08
14
014
1
Tube 1.000 x 0.065
14.08
12
15
015
1
Tube 1.000 x 0.095
54.597
16
016
1
Tube 1.000 x 0.095
14
17
017
1
Tube 1.000 x 0.095
100.814
18
018
1
Tube 1.000 x 0.095
20
19
019
1
Tube 1.000 x 0.049
14.883
20
020
1
Tube 1.000 x 0.049
17.383
21
021
1
Tube 1.000 x 0.049
10.078
22
022
1
Tube 1.000 x 0.049
10.078
23
023
1
Tube 1.000 x 0.065
28.018
24
024
1
Tube 1.000 x 0.065
28.018
25
025
1
Tube 1.000 x 0.049
28.638
68
DISCLAIMER: MODEL AND DRAWING ARE FOR DISCUSSION/ TEACHING
PURPOSES ONLY. THE MODEL DOES NOT COMPLY WITH SAE RULES &
REGULATIONS. IT HAS BEEN MADE AVAILABLE STRICTLY AS A TEACHING
TOOL.
17
67
60
26
026
1
Tube 1.000 x 0.049
28.638
27
027
1
Tube 1.000 x 0.065
32.213
28
028
1
Tube 1.000 x 0.065
32.213
29
029
1
Tube 1.000 x 0.065
34.665
30
030
1
Tube 1.000 x 0.065
34.665
31
031
1
Tube 1.000 x 0.065
30.599
32
032
1
Tube 1.000 x 0.065
30.599
33
033
1
Tube 1.000 x 0.049
3
34
034
1
Tube 1.000 x 0.049
3
35
035
1
Tube 1.000 x 0.049
12.885
36
036
1
Tube 1.000 x 0.049
12.885
37
037
1
Tube 1.000 x 0.049
15.187
38
038
1
Tube 1.000 x 0.049
15.187
39
039
1
Tube 1.000 x 0.049
34.382
40
040
1
Tube 1.000 x 0.049
34.382
41
041
1
Tube 1.000 x 0.049
11.75
42
042
1
Tube 1.000 x 0.049
19.898
43
043
1
Tube 1.000 x 0.049
10.301
44
044
1
Tube 1.000 x 0.049
10.301
45
045
1
Tube 1.000 x 0.049
14
46
046
1
Tube 1.000 x 0.049
14
20
36
38
64
22
32
34
66
63
19
62
30
58
21
56
54
15
28
18
74
69
47
047
1
Tube 1.000 x 0.049
14.242
48
048
1
Tube 1.000 x 0.049
14.242
49
049
1
Tube 1.000 x 0.049
16.923
50
050
1
Tube 1.000 x 0.049
16.923
51
051
1
Tube 1.000 x 0.049
20.312
52
052
1
Tube 1.000 x 0.049
20.312
53
053
1
Tube 1.000 x 0.049
20.024
54
054
1
Tube 1.000 x 0.049
20.024
55
055
1
Tube 1.000 x 0.049
19.069
56
056
1
Tube 1.000 x 0.049
19.069
57
057
1
Tube 1.000 x 0.049
21.341
58
058
1
Tube 1.000 x 0.049
21.341
59
059
1
Tube 1.000 x 0.049
9.047
60
060
1
Tube 1.000 x 0.049
9.047
61
061
1
Tube 1.000 x 0.049
18.456
62
062
1
Tube 1.000 x 0.049
18.456
63
063
1
Tube 1.000 x 0.049
15.548
64
064
1
Tube 1.000 x 0.049
15.548
65
065
1
Tube 1.000 x 0.049
17.427
66
066
1
Tube 1.000 x 0.049
17.427
67
067
1
Tube 1.000 x 0.049
36.978
68
068
1
Tube 1.000 x 0.049
36.978
69
069
1
Tube 0.875 x 0.049
30.195
70
070
1
Tube 0.875 x 0.049
19.285
71
071
1
Tube 0.875 x 0.049
10.909
72
072
1
Tube 0.875 x 0.049
34.971
73
073
1
Tube 0.875 x 0.049
20.8
74
074
1
Tube 0.875 x 0.049
14.171
71
65
46
37
26
31
33
50
59
70
35
44
42
61
40
12
29
57
55
14
27
53
73
24
51
72
16
45
49
25
23
REV'N
DATE
DRAWN APPRVD. DESCRIPTION
43
UNIVERSITY OF ABC
47
SPRINGFIELD, SOMEWHERE, USA
41
11
39
THIS DRAWING OR THE INFORMATION CONTAINED HEREIN MAY NOT BE REPRODUCED
WITHOUT PERMISSION FROM UNIVERSITY OF ABC
13
LINE1
LINE2
LINE3
DRAWN: INIT
'C' SCALE: 1:5
DATE: XXX
PROJECT NO.
DRAWING NO.
PROJECT
DRAWING
REV NO.
X
- pg 12 of 21 -
Cutlist Setup: Steps to take if no description field is present.
1. Check the profiles for the library feature parts. If there is no description field, ensure that the description field has
been filled out. Resave all of the library feature parts once this has been completed. For complete instructions on
setting up library feature parts, please see the Preparing Solidworks for Modeling section.
2. Bring the model tree up by dragging the rollback bar in your DesignTree up to the first structural member. You
will need to open each structural member individually and toggle the library feature (choose a different size, then
toggle back to the desired size); this will add the correct description of the tube to your cutlist. Drag the rollback bar
down to the next structural member and repeat for all tubes.
3. Next, select all of the cutlist item folders and delete them (you may need to turn off ‘automatic’). This will leave the
cutlist folder with only bodies. Right click the main cutlist folder and select ‘update’. This will put all of the bodies
into cutlist item folders. Now check the properties of each folder and notice that there will now be a description
present.
Using other CAD packages: Best Practices
- pg 13 of 21 -
Our preferred CAD package is SolidWorks due to it’s tools for weldments and tube structures but there are a large number
of additional CAD programs that may be used. We will take a neutral file format and import it into SolidWorks in order to
get the cutting toolpaths.
There are some common problems when creating files in other CAD programs and importing them into SolidWorks:
• ‘Sweeps’ are used to make profiles along a line to make the tubes. Sometimes the profiles’ sketch planes are not perpendicular to the line in which they are being swept. This in reality creates elliptical tubing!
• Bent tubes: lines before and after a bend/radius need to be tangent to that radius!
• Broken surface tubes: is caused by a variety of factors, some unknown. Typically caused by incorrect ‘sweeping’ of the
tubes but also caused by saving the file as a ‘surface-body’.
We are able to take files from all other 3D cad programs as long as they are saved as a generic file format such as STEP(*.
stp,*.step), IGES(*.igs) or Parasolid(*.x_t). If using CATIA, the Parasolid (*.x_t) neutral format is preferred. When saving; check
options to verify that the part is being saved as a ‘solid body’ not a ‘surface body’.
The best method to check if the solid model is suitable for us is to open it up in SolidWorks if you have access to it. Open
the parts and check that they look visually correct and that they do not open with any errors (typically the errors would be
surface errors which are a problem). Turn on ‘view\Temporary Axes’, and there should be axes along the centerline of the
tube.
A common import problem is a split body. This tube when opened in Solidworks has a seam along the centerline cutting
the tube in half. In order to solve the problem, please check that the file is saved as a ‘solid body’. Saving it as a different
neutral file format may also remedy the situation.
Bending: Information and Guidelines
- pg 14 of 21 -
Our tube kits include the formed or bent round tube components in most cases. The value and convenience of our combined profiled and formed tubes is exceptional. However, there are restrictions and limitations. Note that we profile the
tube as a straight tube and then bend with the correct orientations and bend allowances. The critical step is setting up the
procedure. There are many factors and variables in the bend process that require concise procedures and a knowledgeable
operator. However, once it is set up, consistency and repeatability are very good. Bending is about 80% science and 20%
art. We can produce formed tubes with multiple bends in different bend planes subject to restrictions. However, ‘simpler is
better’.
1. Bending Constraints
• All of the tubes are bent with an electric rotary bender. There is no mandrel on the bender so there are limitations to
the size of the bend radius relative to the thickness of the tube.
• Bend radii must be selected and modeled corresponding to the dies we have available and appropriate for the tube OD
/ wall thickness / bend angle required. See the attached document.
• There is also a minimum distance between bends of 4-5” typically for out of plane bends. This distance can be slightly
reduced if the bends are in the same plane.
2. Example Bent Tube Component
Example: 0.750” OD x 0.058” wall tube. It has 2 bends which are out of plane from one another; this is why there is a minimum length of 4” between these bends. There is also 5” minus the profiles on the end of the tube to allow for bending.
The centerline radii of these bends are 46mm/1.811”; this is allowed because the tube has a 0.058” wall. The thicker the
tube, the easier it is for us to bend. If this tube was 0.049” wall, we would not be able to bend it with the 46mm/1.811” radius; the radius would have to be larger; you would need to use the 67mm/2.638” radius.
3. Modeling considerations for bent tubes
All the radii in a bent tube need to be tangent to the
straight sections before and after the radii! It is geometrically impossible for us to bend a tube where
the bends are not tangent to the straight sections.
An easy way to check if your bent tubes are correct
is to make a 3Dsketch with lines on the axis; all of
the lines should be able to connect to one another
in succession.
If using a different program we prefer to have all of
the tubes as .stp or .igs formats. When saving parts
under this generic format, make sure that you are
saving your solid bodies as solid bodies (Not surface
bodies).
How to check: Should have a temporary axis (means
that it is a solid body).
Bending: Die Chart
- pg 15 of 21 -
The following are constraints and preferences of our tube bending process when combined with end profiles:
1.
2.
3.
4.
5.
6.
7.
Tubes are formed using bending dies specific to the tube outside diameter and centerline radius.
Thicker wall tubes can be bent to tighter radii.
Thinner wall tubes have minimum bend radii and limited bend angles.
Bend angles greater than 90 degrees require thicker walled tubes.
Shallow bend angles less than 20 degrees can sometimes be achieved with thinner wall tubes.
Minimum distances between bends are required for multiple bends, typically about 4.00” inches.
Minimum straight tube lengths of approx 4.00” are also required from the end of a tube to the start of a bend. This is
required to properly support the tube during bending.
8. Minimum bend radii are also subject to the material properties.
9. Refer to the chart for bending dies currently available.
10. If possible by design, consider using the larger bend radius.
Tube OD (in.)
Centerline Bend Radii (mm/in)
Minimum wall thickness (inches)
(in.) (mm/in.) based on 90 degree bends. Thinner walls
are not recommended but may be achievable on bends
< 20 deg
0.375”
36mm / 1.417”
>or = .035”
0.500”
36mm / 1.417”
>or = .049”
0.625”
46mm / 1.811”
>or = .049”
0.750”
46mm / 1.811”
>or = .058”
67mm / 2.638”
>or = .049”
98.4mm / 3.875”
>or = .049”
6.000”
>or = .035”
46mm / 1.811”
>or = .083”
67mm / 2.638”
>or = .049”
56mm / 2.205”
>or = .120”
67mm / 2.638”
>or = .095”
82mm / 3.228”
>or = .058”
149.2mm / 5.875”
>or = .035”
67mm / 2.638”
>or = .083”
82mm / 3.228”
>or = .058”
82mm / 3.228”
>or = .120”
112mm / 4.409”
>or = .065”
82mm / 3.228”
>or = .083”
112mm / 4.409”
>or = .049”
100mm / 3.937”
>or = .083”
150mm / 5.906”
>or = .065”
1.625”
130mm / 5.118”
>or = .083”
1.750”
150mm / 5.906”
>or = .083”
170mm / 6.693”
>or = .083”
150mm / 5.906”
>or = .120”
190mm / 7.480”
>or = .083”
0.875”
1.000”
1.125”
1.250”
1.375”
1.500”
2.000”
½” pipe (.840” od)
R56mm (2.205”
¾” pipe (1.050” od)
R67mm (2.638”)
1” pipe (1.315” od)
R67mm (2.638”)
R112mm (4.409”)
1 ¼”pipe (1.660”od)
use 1.625” OD tube die (R130mm /
5.118”)
Weldment Design: Square Tubes
- pg 16 of 21 -
• We can also produce profiled square tubes. Square tubes can be very
beneficial as design features for mounting components onto the
chassis structure.
• Cutouts on square tubes need to have a minimum 0.010” offset from
the inside face.
We suggest using round tubes wherever possible. Consider the following:
• Our preferred sizes are 1.000” square x .035”, .049” or .065” wall thickness.
• See the Weldment Profiles: Selection and Use for sketch profiles noting the required corner radii.
• Square tubing raw material is much more expensive than round tube raw material.
• It is also more expensive to set up and profile square tubes.
• Simplify the trim sequences and resulting trims on square tubes.
• Avoid ‘mitering’ square tubes wherever possible.
• Square tubes cannot be formed or bent.
• Square tubes ‘nest’ onto round tubes very well but are difficult to nest and trim into complex clusters with round
tubes and multiple sizes. Simpler designs require more effort but are more economical to manufacture and much
easier to locate, align and assemble downstream.
Weldment Design: Trimming Options and Guidelines
- pg 17 of 21 -
The sequence and options used when trimming is incredibly important to the weldment design. Below are several
common areas where errors occur in weldments and need to be done in the correct method and sequence. In some
situations, having incorrect trims negates having CNC profiled tubes. Proper trims will allow for easier and more
accurate fabrication. Please review the situations below carefully to ensure that you follow the proper procedure. The
majority of models which we receive have most of their errors in the trims. Missing trims, improper trims and hollow
nodes are the most common mistakes.
General Trimming Procedure
In SolidWorks, the general procedure for trimming is as follows. In certain situations, different options are used in order
to create a proper trim.
1. As you build up the weldment, create and place structural members (tubes) in the order that you will be fabricating
the structure.
• Use a unique structural member for each tube. Do NOT put all of the same size tube in one structural member
definition. Using a unique structural member allows for easier change of tube size.
• Trim the tubes as you create structural members, rather than doing all of the trims at the end of the design tree.
This limits missed trims in tube clusters.
• Trim in the order you will place tubes. Ensure that there are no hollow nodes in any cluster.
2. Trim a single tube at a time, both ends. If you are having difficulty with a trim, do one end at a time. DO NOT trim
multiple tubes in one operation, this leads to confusion, errors and limits ability to parametrically change the
model. Having organized trims allows for ease of modeling and verification.
3. For options, use the ‘Trim to Body’, do not ‘Allow Extension’ settings as a base point. If trimming to bodies does
not create a correct resultant trim, set the Trimming Boundary to Face/Plane. Check the bodies to keep and the
trimmed bodies to discard. Review that the trims have been completed using the surface are correct.
Specific Trim Issues : Hollow Nodes
• Hollow nodes occur
when all of the tubes
are trimmed to all
the tubes which they
come in contact with.
correct trimming order
tubes trimmed to each other, incorrect hollow node
• This causes seams
and nodes which only
contact on the edges
of the tubes; thus creating hollow nodes.
• This makes the kits
difficult to weld and
it makes the nodes
structurally weak.
• Ensure that the trimming sequence is
done in a way that
eliminates hollow
nodes
correct trimming order
tubes trimmed to each other, incorrect hollow node
correct trimming order eliminates hollow node
Weldment Design: Special Design Considerations
- pg 18 of 21 -
Specific Trim Issues : Trim Extension
• Choosing the ‘allow
extension’ option
in the Trim Feature
can lead to improper
trims in a tube cluster.
• Ensure that all
clusters are trimmed
properly by visually
inspecting trims before you send the file.
correct trimming options
correct trimming options
allow extension selected, incorrect trim
allow extension selected, incorrect trim
Specific Trim Issues : Trim to Mitre
Trimming to a mitre is a specific case where the Trimming Boundary needs to be set to Face/Plane. Ensure that the trim
that is completed is correct. Choose which body to ‘keep’ or ‘discard’ by toggling the body callouts.
correct trim settings, using surfaces as trimming boundary
incorrect trim, mitre is not properly trimmed to
- pg 19 of 21 -
Specific Trim Issues : ‘Toothy’ Trims
There is a specific case where the initially the trim looks satisfactory, but when the individual files are pulled apart and the
trims are verified, tubes may show ‘toothy’ gaps. As our process takes the 3D model in order to extract the CNC data, this
will cause an incorrect part.
This error is caused by using the BODIES option in the Trimming Boundary setup. The correct method in this situation is to
use the FACE/PLANE option, as shown below.
INCORRECT options
CORRECT options
Using the FACE/PLACE option in the
Trimming Boundary setup results in a
complete trim on the tube to be cut.
Please ensure that you visually inspect
all parts and trims in your weldment
before saving as an individual part.
Revise any trims with errors.
SAE Student Projects
- pg 20 of 21 -
Creating a Model
Most teams start their suspension node sketches and build their cars
around their suspension. We recommend doing a side view of the car and
determining the fit of the driver within the car. FSAE has made a model
of what a 95 percentile male will look like and call this model “Percy”. The
figure shows what Percy looks like according to a FSAE Workshop. We
encourage putting “Percy” in your right side view of your FSAE chassis
design to make sure spacing is correct.
From pg20 of FSAE Workshop 10.25.2008
Fully define the sketches when building the wireframe. Fully defined
sketches helps with the stability of the model. Breaking the model down
into several sketches is also very important. Some teams attempt to put
all of the tubes in a single 3Dsketch and this makes it very difficult to
adjust; it also makes SolidWorks less stable and makes design changes
difficult to implement. We recommend doing a separate 3Dsketch for
each of the bent tubes. Bent tubes must follow the “Bending Die Chart:
Guidelines” Document. See the Bent tube section of this document for
more details and examples.
Student Project Bent Tube specifications
All of the tubes are bent with an electric rotary bender. There is no mandrel on the bender so there are limitations to
the size of the bend radius relative to the thickness of the tube. There is also a minimum distance between bends of
4-5” typically for out of plane bends. This distance can be slightly reduced if the bends are in the same plane.
Here are some examples of what main roll hoops look like for Formula SAE projects:
Single Large Radius
Double Smaller Bend
A good practice for the bottom of bent roll bars is to leave the roll bars a bit long and trim all of the other tubes to it.
Another good practice is to miter the bottoms of the roll bars with the cross tubes.
We prefer that Roll hoops have all of their bends in a single plane so that it is easier to ship and lower shipping costs to
customers. However we are fully capable of bending multi-plane bent tubes as long as our guidelines are followed.
For additional information and a full list of constraints, bend die sizes and best practices, please see the Bending
Guidelines document.
VR3 Engineering Ltd.
45 Dunlop Place,
Stratford, ON CANADA
+1 519 273 6660
info@cartesiantube.com