Opinions on this router design

[NB70]

What do you think of this design for a router? It is based on the other build threads here - it would be used for hobby wood working, occasional plastics and it would be useful to have it make replacement aluminium parts for itself. The range of motion is 1160 X 600 X 160mm - I'm aiming for around a quarter size sheet of plywood cutting area. I'm planning on using 1610 ballscrews on the X and Y, with a 1605 on the Z.

The base is 50 X 50 X 3mm welded steel box section. Plates with bearings or rails will be 20mm ecocast aluminium. The gantry is two pieces of 90X45 aluminium profile in an L-shape - from one of JazzCNC's original designs. The rails and bearings are the Hiwin type 15mm guideways - I will mount them on epoxy for the X-axis and directly to the aluminium profile for the Y (if this is possible?).

To keep the initial costs low I will start by using some components I already have with the plan to upgrade later. I will use the stepper motors, power supplies and drives (M542s) from my existing machine - an MDF router. Also I will design the frame for an 80mm 2.2Kw spindle but initially I will be using the Kress routers I already have.

What do you think?
Nathan

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[routercnc]

Hi Nathan,

Good start in many areas:

Ballscrew choice - good
base 50x50x3 - OK for wood, possibly go a bit bigger
20mm ecocast plate - good
gantry 90x45 'L' - fine for wood and occasional aluminium
rails 15mm - bit on the small side for mounting nicely to profile on Y (I used 20mm rail on Y to span the slots better). Ok for X to steel box section, and Z onto plate.
M542 - OK, mid-level drives and you have them anyway so may as well start off there.
Spindle - Kress, ok but noisy. 2.2kW WC spindle upgrade WELL WORTH IT.

Layout:
I would raise the x-axis rails to avoid having 'gantry sides' and allow a more direct mounting of the gantry to the x-axis bearings
The x-axis ballnut mounting plate (yellow) looks too weak - this will limit the x-axis stiffness as seen by the cutter
The y-axis ballnut mounting 'plate' looks too weak and offset - I would move the Z stepper motor (e.g. turn it on it's head and mount on posts to free up space) and get a better connection to the y-axis
Add another set of holes in the Z plate for the motor mount. This will allow you to move it up on the plate for different jobs.

[NB70]

Thanks for the useful feedback - you've given me some good ideas to improve the machine!

Nathan

[JAZZCNC]

Ok well I hardly anything wrong here just a few pointers gained from building the design you've copied.

First keep the gantry sides don't get rid of them as you want them to lock and locate the profile but like Routercnc says they will be better sat direct on the bearing plates thou you'll need 2 plates to do this. One fastens to bearings and the other is bolted to gantry which bolts to bearing plate. Doing this gives you more adjustabilty as well has strength as you can loosen or shim the top plate to aid squaring and setting up if needed.
Also put the gantry sides on the out side and make it one piece that drops down so ballscrew fastens to it. This gets rid of that brace which won't be needed now and the profile sits directly on and above bearings giving better direct loadings etc.
One thing with your design having profile on inside is that it doesn't leave much room at the rear for everything to fit and not clash. It will fit I know that 100% because my router design(see pic) uses it in same way but it's very close but if you use suggestion above the profile is that bit longer and you have more room for switches etc.

With the Y/Z axis then I'd flip the motor and ballscrew mount to other side. Couple of reasons for this, You can make the ballnut bracket support larger which makes it stiffer. The way you have the brace means it's very short due to the ballnut flange so doesn't give much support, if you flip to other side you gain about 10mm in length which makes a differance. Also make the drop bracket out of thicker plate 20mm minimum.
Other reason is cable routing it just makes running cable chain and wires runs shorter and more fluid.
Wouldn't bolt the plate that holds motor from top instead bolt from front has it will support the Y axis rear plate better and make it from thicker material ideally 15mm minimum 12mm. If you use 15mm you won't need the little upright support which will be a pain to fasten.
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With the base then you'll need to brace those sides with triangle plates or supports at each end else they could vibrate which will show in cut.
Like Routercnc says you'll need to beef the motor mounts etc and looking at your model I think your short on the ballscrew length be careful not to try to work to fine on screw/rail lengths as it's very easy to miss calculate and run short of your target cutting area.

[NB70]

Thanks for the taking the time to post those detailed tips - I'll go back and change the design & hopefully re-post it when I get back from holidays.

[Boyan Silyavski]

Make it from 80x80x3 and you will have little beast that can deal easily with aluminum.

[biketrialsdave]

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Jazz - Do you have a link to the build thread for this design please?

[JAZZCNC]

Jazz - Do you have a link to the build thread for this design please?

No there isn't one sorry.!

[Boyan Silyavski]

No there isn't one sorry.!

Dean, it's time you make plans for this one and start selling them.

It seems that will be the design that people who are inclined to pay are inclined to build.
And at the same time you will be doing them a favor, having in mind the shi#ty designs I have seen for sale and i mean not only the plans but the machines also...

[mekanik]

Dean, it's time you make plans for this one and start selling them.

It seems that will be the design that people who are inclined to pay are inclined to build.
And at the same time you will be doing them a favor, having in mind the shi#ty designs I have seen for sale and i mean not only the plans but the machines also...

Second that but does he he have the time ?
Mike

[biketrialsdave]

No there isn't one sorry.!


That's a shame. Do you have an album containing all the photo's which you'd like to share? I am particularly interested in how you have attached the BK/BF blocks to the extrusion as I thought the hole spacing was 6mm out?

Dave

[JZimmy]

That's a shame. Do you have an album containing all the photo's which you'd like to share? I am particularly interested in how you have attached the BK/BF blocks to the extrusion as I thought the hole spacing was 6mm out?

Dave

haha, I started designing my router the other week and noticed this as well... I went through a ton of build logs and everyone seems to do it but not exactly sure how. Do people typically just drill/tap the extrusion? I was considering moving to the WBK bearing style and mounting in the side plates when I noticed this.

- JZ

[Nr1madman]

haha, I started designing my router the other week and noticed this as well... I went through a ton of build logs and everyone seems to do it but not exactly sure how. Do people typically just drill/tap the extrusion? I was considering moving to the WBK bearing style and mounting in the side plates when I noticed this.

- JZThe way to do this is to buy 45mm extrusion. Then you are 1mm out of perfect alignment but it will fit :)

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[JZimmy]

The way to do this is to buy 45mm extrusion. Then you are 1mm out of perfect alignment but it will fit :)

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Well that makes a lot more sense, thanks! I still might go with the WBK bearings as I might be able to fit the ballscrew under 20mm rails without having to space them... not sure if its possible yet, it will be very tight.