LR4 questions...Time to jump in

LowRider CNC Advice
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Ok…After a year of waffling around, and hemming and hawing…I’ve decided to actually put a plan in place to move forward on a LR4 to be used as a fabric Plotter/Cutter.

Plan is to use a SST drag knife for cutting, and a pen mount for plotting.

This will be used for fabricating large Canvas panels, Clear Enclosure panels, Cushion fabric cutouts etc etc.

First question being…. “X” axis….i.e. width…. The fabrics I use usually come in rolls 61” wide… Can the “x” axis be increased to accomadate the full fabric width?

I am not so concerned with the “Y” axis as that is basically unlimited..I.E. rail lenght, chain drive, wiring etc etc etc. I would like to start with an 8’ “y” axis… I can always increase that down the road…

I suspect that 90% of the use will be drag knife cutting…

Yes, I intend to use a vacume table, homebuilt, sealed bottom panel, permeable spoilboard.

Push me over the edge here guys….. My x-mas present to myself will be a call to Northwoods Creations and a CC # lol….

Keep in mind, I am a complete CnC virgin…software, use, the whole 9 yards… talk to my in purple crayon…

Thanks

Agflit

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For a drag knife, probably.

For this application, you’d want to have aluminum strut plates and PET-CF braces.

Essentially, you’re going to need a super stout beam for that machine.
It’s WAY off the “yellow brick road”, so it’s a custom attempt at making a machine.

Probably something JJ and company can help with. Shipping that sucker isn’t going to be fun.

You’ve got a lengthy workflow / learning process. The community can help you, but there’s no such thing as turn key here for a cloth cutter drag knife setup. You’ll have to commit to learn as you go, else you should be looking at the much more expensive commercial solutions.

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As long as the box stays at or under 8’ UPS will ship it without freight charges. I buy bundles of 3030 extrusion in 96" lengths (annoyingly not 98") to avoid UPS freight charges once boxed. I think a boxed 61" usable span LR4 gantry may end up to be a similar volume and slightly shorter length, so UPS may be an option. Boxing itself may be a little more fun than normal, but not super different.

Of course, ordering parts and self-assembly is also an option that lots of us here will ‘help’ with.

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I can do just the printed parts. Or I am about to add a “partially” assembled option with the YZ plates and core all put together but no EMT or built beam. If either of those could help @agflit please don’t hesitate to ask!

Can also very much go this route. Let me know if you are interested and we can figure out a price for that width of machine.

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Thanks for the reply..sent you a dm

agflit

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Just a quick update…

Can’t say enough nice things about Jonathon and Northwoods Creations in regards to original post… sent him a DM, and received a phone call within hours!!

Naturally, being a complete ignoramous about everything involved, I had LOTS of questions… and man, he was great!! Took all the time needed, was patiant, explained things clearly, offered suggestions and options, and was more than willing to help me along with information needed to actually make informed decisions.

So, at this time, we are discussing whats needed to go 60” X axis… and increase rigidity in the gantry.

Just wanted people to know how forthcoming and passionate he is about the LW4. A great asset to the community!!

agflit

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Thank you so much for the kind words! Looking forward to seeing this project come to life! It will be the largest LR4 I have seen for sure! Should be a fun one!

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JJ’s been a great community member for a good while, before becoming authorized to sell assembled machines and subassemblies.

I will be watching with interest as you make progress.

I hope you’ll continue to share details about your work flow and the drag knife setup that you create.

We love seeing this kind of project, even if it’s well off the beaten path for ‘normal’ builds.

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jj-dynomite

IYKYK…

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Ok…First things first…information is power right?

X axis rigidity.. ( and PLEASE…jump in and put my brakes on if I am completely wrong on anything all…).

As I understand..( I’m no structural engineer)… X axis and rigidity have 3 areas that can be looked at…

1- the closer the spindle etc is to work surface the less deflection as a result of moment arm influences…( leverage right?) in this case…less is more.

2- Literal Beam rigidity… only so much I can do here…I am leaning toward 1/4” Aluminum in leu of MDF or even a hardwood strut plate…. would increasing the # of Strut braces have any meaningful impact on rigidity?

3- Vibration isolation and keeping linear rails “loaded”… Should I worry at all about beam deflection actually impacting the “guide” contact with the rails?…if that makes any sense…

My Plan regarding the router/spindle…is to keep the “Z” axis close as possible to the work surface in order to negate any deflection issues as a result of moment arm influence… keep in mind, I’m cutting fabric here, literally a few pounds of downforce when the drag knife is working….

I’m sure this is just a atart of a long and interesting road…every journey starts with the first step… (now, watch me trip on my own feet lol..)

Interested in anything anyone has to say, open to input, and yes, I will try and keep updates as the thread unravels lol..( pun intended)

agflit

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Correct. The LR4 is designed that the lower the beam is the more rigid it is.

I cant say for sure if adding more braces helps or not. But I have an extra added in my personal LR4 and for as hard as I push it I don’t have noticeable deflection issues. I do think the Aluminum will help make it even stronger than plywood/MDF struts, but at what you are planning to do I am not 100% sure if it will be needed or not. I believe we also talked about printing ALL of your braces out of PET-CF for added rigidity which @MakerJim also suggested.

The weight of the beam should be plenty to keep this a non issue. Even more so if you are planning to use a Carbide3d router as your drag knife holder.

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Width of the beam also plays a role in rigidity. Building to an appropriate size for your needs is recommended. Overbuilding the width is not.

Beam width also affects overall mass (and therefore acceleration). Not crucial for mounting a router, but might affect laser speeds.

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My how the world turns…lol.

So, As you all know, the plan is to build a LR4 for plotting/cutting marine fabrics…. think boat covers, canvas etc etc.

Being a complete virgin to every facet involved, i.e. Cad/Cam, g-code, cnc etc etc… My work flow was intended to be…Order parts from Ryan and/ or Northwoods and basically simply build the table, and install the mostly completed gantry….

After speaking with Jonathon, I was making final arrangments on my end ( budget etc etc)…to pull the trigger.

Now…for those of you who have a very good friend who is a professional EMS Life Flight pilot, be very careful what you share lol…

My buddy, upon hearing my plan, informed me he has been 3d printing for some time, is a real nerd at times, and thinks the whole LW4 build is a great idea…

So…guess what shows up on my door last week?…. yup, a Flashforge 5M, several rolls of pla in matte black, copper bronze, and emerald blue…. with a note. Learn to print, it’s not that hard, and you’ll have a much better understanding when you build/assemble/ and operate the cnc.

Hard to argue the point I guess….lol. So, I guess I will be going down the “ 100% diy “ road for the most part.

And, man…3d printing is SO cool…amazing, just freaking amazing. So far have printed entire full enclosure parts, fabbed the clear polycarbonate panels, and am about to assemble the 5M enclosure.

Once I have established stable temps wioth enclosure..I will start printing LR4 parts!!

I will try and maintain an ongoing log for the community, given the “x” axis size involved.

Plan right now is usable dimensions of 60” X 120”. I think an aluminum strut plate may be in my future lol.

agflit

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I need better friends…

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Yeah, Jonathan and I are not buying you shit, mister! :joy::sweat_smile:

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That was EXACTLY what I thought ! LOL

Edit: In all seriousness, what an awesome friend. We all do indeed need to be that kind of friend for each other.

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Pretty sure I sent you a whole ERCF sir! :rofl:

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lol… I didn’t call you out by name…

You feeling guilty it wasn’t a printer?!?!?

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Not at all. Calling you out for saying you dont have good friends that send you stuff :rofl: :rofl: :rofl:

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I was meaning the people I’m around all the time.

I talk to a lot of people in person about the things I want to do.

They all look at me like I’m crazy.

None of them buy me things to help make it happen…

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