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Frame

Estimated time: 3 hours

This page will guide you through assembly of the T-slot aluminum frame.

CAD model

To build the frame, please follow the design in the CAD model. Below, we link to an online viewer where you can navigate the CAD model directly in your browser.

Click to open online CAD viewer in new tab: [Onshape]

Click to open online CAD viewer in new tab: [Onshape]

Click to open online CAD viewer in new tab: [Onshape]

Tip

To rotate the Onshape 3D view, hold down the right mouse button and drag. To identify a part, click on it in the 3D view, and its name will be highlighted in the parts list on the left side. You can hide and show parts to improve visibility. For more tips on navigating the user interface, please see the Onshape docs.

We also provide the following drawing which shows all relevant measurements (in mm):

Parts

You will need the following parts to build the frame:

Item Quantity
2020 500mm rail 13
2020 250mm rail 4
2020 28mm gusset 24
2020 20mm gusset 8
2020 90 degree plate 24
2020 20mm corner bracket 8
2020 M5 slide-in T-nuts 222
M5 8mm screws 174
M5 10mm screws 48
Item Quantity
2020 500mm rail 16
2020 300mm rail 4
2020 28mm gusset 20
2020 20mm gusset 8
2020 90 degree plate 20
2020 20mm corner bracket 32
2020 M5 slide-in T-nuts 237
M5 8mm screws 197
M5 10mm screws 40
Item Quantity
2020 400mm rail 12
2020 250mm rail 4
2020 28mm gusset 16
2020 20mm gusset 8
2020 90 degree plate 20
2020 tee plate 2
2020 20mm corner bracket 8
2020 M5 slide-in T-nuts 201
M5 8mm screws 158
M5 10mm screws 43

Note

Some parts come with hex keys included:

We recommend discarding these, as they are typically low quality and can strip easily screws.

Note

The 90 degree plates come with their own screws (right). We recommend discarding them as they look very similar to the 8mm screws but are not as strong.

This table shows what screw and T-nut should be used to install each part:

Item Screw T-nut
28mm gusset Included Included
20mm gusset 8mm Slide-in
90 degree plate 8mm Slide-in
Tee plate 8mm Slide-in
Corner bracket 8mm Slide-in
Top plate (3mm acrylic) 8mm Slide-in
Bottom plate (6mm acrylic) 10mm Slide-in
Caster module 10mm Slide-in

Note

You will find 3 kinds of T-nuts:

We will primarily use slide-in T-nuts (left), which need to be pre-installed since they are placed from the end of the rail. Roll-in T-nuts (middle) can be used if you forgot to pre-install a slide-in T-nut. We recommend discarding all of the drop-in T-nuts (right), as we will not use any of them.

Note

The 28mm gussets come with their own screws and T-nuts (middle), which are slightly different from the standard M5 screws and T-nuts (right). The screws for the 28mm gussets have wider heads to accommodate the larger mounting holes in the gussets.

Note

For all other parts, we will use these 2 types of M5 screws:

Most parts will use the shorter 8mm screw. The longer 10mm screw should be used when mounting thicker parts, such as the caster modules and the bottom acrylic plate.

Assembly

Please follow the CAD model to assemble your frame. We break down the process into more detailed steps below, but feel free to assemble in any way you prefer.

Note

The frame uses hex screws in metric sizes only. To avoid accidentally stripping screws, do not use any Imperial hex keys during frame assembly. If you are using Bondhus hex tools, use only the red ones, not the yellow ones.

Tip

Before starting the assembly process, gather all parts and lay each one next to where it will be installed. This helps ensure that all parts are accounted for.

Tip

Make sure screws are tight. Vibrations from robot movement may cause screws to loosen and fall out.

Tip

Screws should go in smoothly and not feel tight until they are fully seated. If you find that a partially inserted screw is difficult to turn, it is most likely due to a misalignment. Please loosen the screw and check the alignment, do not force the screw in.

Bottom frame

Start by assembling the bottom frame:

Note

There are two sizes of gussets: 28mm (left) and 20mm (right).

We primarily use the larger 28mm gusset, but there are 8 locations where the smaller 20mm gusset must be used, as shown in the image below. If the 28mm gusset is used in any of these locations, it will collide with the caster module, preventing proper installation.

Note

Please pre-install slide-in T-nuts for the caster modules and the bottom acrylic plate:

Item T-nuts
Caster module 32
Bottom plate 16
Item T-nuts
Caster module 32
Bottom plate 8
Item T-nuts
Caster module 32
Bottom plate 11

For the caster modules, each corner of the bottom frame should contain 8 T-nuts like so:

For the bottom acrylic plate, please refer to the mounting hole locations in the CAD model for T-nut placement.

Note

If the bottom of your frame is not level, your mobile base may have one wheel constantly off the ground. Before you install the middle crossbars, place your bottom frame on a flat, level surface like a tabletop and check whether it rocks back and forth.

Top frame

Assemble the top frame:

Note

If you will be using the top acrylic plate on your mobile base, please pre-install the corresponding slide-in T-nuts for mounting the plate:

Item T-nuts
Top plate 22
Item T-nuts
Top plate 17
Item T-nuts
Top plate 16

For T-nut placement, please refer to the mounting hole locations of the top acrylic plate in the CAD model.

Uprights

Attach the 4 vertical rails to the bottom frame:

Tip

For this step, we found it helpful to turn the frame sideways to prevent the T-nuts from moving around during screw installation.

Complete frame

Put together the top and bottom parts to complete the frame:

Tip

We turned the frame sideways for this step as well. Make sure to pre-install T-nuts in the vertical uprights before attaching the top frame.

Note

The top and bottom acrylic plates will be installed later as part of Integration.