Fusion 360 tab & slot welding table.

[BelgiqueB]

Hi, I'm 'designing' a welding table in fusion 360 using the tab and slot design, how much tolerance should i leave between the tab and the slot? I imagine if i have a 30x5 slot and a 30x5 tab I'll have difficulty fitting everything up? For now i've made the tabs 30mm long and the slots 30,1 mm long, no idea if this enough, too little or too much.

Anyone have experience with this?

 

[Agroshield]

It may depend on what process you are using to cut the parts. Laser may well be different to plasma may well be different to water. Material thickness may also have an influence. Read up also on material thickness tolerance so you do not get caught out that way.

Do a small test part and then you will know.

 

[hotponyshoes]

If you want it really accurate I would be tempted to leave at least one tab pair on each side with no clearance. Fit with a nylon hammer or freezer spray to ensure the initial setup is right.

As said above, each cutting process will have tolerances available for the size/type of material so you would need to look those up to get any idea of how much allowance you might need.

 

[BelgiqueB]

Forgot to mention, pieces will be lasercut out of 5mm plate.

Found some more info on youtube, 0,1mm seems to be about right according to the original weldflat tables designers.

 

[cr500dom]

laser cut then do it size on size, you wont have any more than a tap together to assemble, ive done loads of jigs and fixtures up to 12mm thick like this

 

[Dev]

You could define a ‘kerf’ user parameter and use that in your design instead of specifying a measurement - that way you could adjust it once for whatever process and it would update the whole design.

This video explains it really well -

If you wanted to be really swanky you could specify user parameters for the hole size, their spacing, material thickness, tab interval. The world’s your edible mollusk!

I’d love a copy of your design if you’re willing to share it, I want to do the same thing.

 

[James1979]

I am building one at the moment from a design I downloaded from 'plasmaspider'. I did talk about it in another thread so I wont bore everyone with it again here, but the guy who designed that did it to be laser cut and has offered it for plasma users. There were a few issues with fit up so he drew up a small test piece, literally 2 tabs and 2 slots. The idea was, cut both, test fit, adjust drawing, repeat as required.

May be a way to do it? Depends if your laser cutter contractor will do a test piece for you?

 

[Welderpaul]

Laser cut tolerance is generally accepted as 0.1mm, but some cover themselves and state 0.3mm. If you specify the tag at 30.0mm, it could end up being 30.1mm. If you specifiy the slot as 30.1mm it could end up being 30.0mm (worst case), meaning its going to be hard to fit. You'll also have the same tolerance in tag position as well as tage size so if there are multiple tags these could end up being out with slots in a cumulative fashion.

Note the 0.1/0.3mm tolerance is usually stated over a certain distance so be wary of that. I'd expect a 0.1mm tolerance on a part 10mm long. A 0.1mm tolerance on a part 6000mm long might be asking too much.

Best to involve the laser cutter and get them to offer some help on what tolerance you should leave. Involves them too if there is subsequently a problem..

 

[BelgiqueB]

Thanks for all the info guys, haven't actually ordered the parts, i'm still stuck offshore for work due to this corona stuff, day 55 today .

As soon as I'm back home I'll phone the company and ask for their advice.

 

[Dev]

.1mm is apparently easily within the capabilities of waterjet as well so having a parametric offset probably isn’t needed after all.

 

[BelgiqueB]

Had the parts laser cut and put in a 0,1mm tolerance on the tabs and slot, they fit together really nice, a couple of light taps with a hammer and everything was nice and snug.

Put my 'precision' ground ruler along the table and not light visible, so more than straigth enough for the type of work i do!

I already had one tab and slot table I bought a 'kit' from a local supplier, cost was 450 euros for a 140cm by 90cm table. The table and the three support beams i had lasered myself cost me 570 euros.

 

[Brad93]

Nice Tetrix

 

[Brad93]

Did you put ribs and corner braces in your design?

 

[cianh91]

we do this fitment quiet a lot for varying customers and thickness . i always recommend a .1mm over on slots any more becomes sloppy if the material isn't full thickness just remember 5mm might be 4.85-5.1 thick generally it will be within .1 of thickness but it does vary slightly.
also if the operator puts a bigger nozzle in a laser it will increase hole size marginally so specify you tolerance to the company as its quite regular for a 1.2 to be used instead of a 1mm on lasers .

 

[BelgiqueB]

Did you put ribs and corner braces in your design?

Put in some braces, nothing original, it's all copied from the certiflat website to be honest :-). But does feel very rigid and is suprisingly straight. Made the 2 table and the connection beam design some flexibility in mind, but with hindsight i should've just made 3 tables instead of 2 tables connected with the beams. Pricewise it would've been around the same price.

 

[BelgiqueB]

we do this fitment quiet a lot for varying customers and thickness . i always recommend a .1mm over on slots any more becomes sloppy if the material isn't full thickness just remember 5mm might be 4.85-5.1 thick generally it will be within .1 of thickness but it does vary slightly.
also if the operator puts a bigger nozzle in a laser it will increase hole size marginally so specify you tolerance to the company as its quite regular for a 1.2 to be used instead of a 1mm on lasers .

The company I used is a smallish company, the guy who ran the laser machine even called me during the input of the files to ask some specific questions, they are 'on the ball' so to say :-) and think along with design. On top of that they are very quick and a good price .

 

[Brad93]

Would you be interested in selling the design or even making a bigger on?

 

[BelgiqueB]

Would you be interested in selling the design or even making a bigger on?

I can send you my files if you'd like, there is also several different sizes you can download for free on grabcad website.

 

[tom2207]

Would you be interested in selling the design or even making a bigger on?

Ive a set of files I got given for a bigger heavier table , Ive not had them cut but Ill send you a copy if its any use , even as a starting point.

 

[Dev]

I can send you my files if you'd like, there is also several different sizes you can download for free on grabcad website.

I’d certainly like a copy if you don’t mind.