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You need a two-part resin of some sort. Search on "room-temperature vulcanized" rubber, or "RTV rubber". There may also be epoxies that are designed to dry rubbery. You want stuff that comes with an activator -- if it's single-part RTV it depends on drying or on oxygen in the air to kick off, and you're back to never curing. Your challenge will be to ...

5

Instead of trying to mold a liquid, you could try to form a viscoelastic solid. That way, the uncured material would keep its shape without an airtight mold. There's a product called Sugru that you might try; it's hand-moldable silicone rubber that dries in air. (I am not affiliated with their company.)

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Actually, you can perform most milling operations with a file, a micrometer, and patience.

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LinuxCNC is an open source project dedicated to "converting" G-code into motor commands. It is not at all a simple task. The basic steps are: Read the G-Code file into memory Interpret the G code (mostly motion commands and way points, but also branches and loops) Plan a continoupous path between the waypoints Add the time dimention to your path (...

3

The location of the homing position does not make any theoretical difference, you can zero (or set to any constant value) your axis positions at any desired position. From a pracitcal point of view, you can consider the following aspects: switches might get in the way of chips, switches might be damaged or the other way around, switches might get in the ...

3

I have worked on a cartesian robot with similar requirements† as your own, and we selected direct drive synchronous linear motors for our x/y stages. In our case, both axes were around 2m in length, but magnet the tracks have the potential to be as long as you need to build them. † Less than an order of magnitude higher at $2/5ms^{-1}$ ...

3

Look for a makerspace in your area, in boston there is http://artisansasylum.com/site/ they have various CNC machines, laser cutters, Etc. which with some simple low cost training you are allowed to use.

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As John Williams points out you can find desktop metal milling machines that are reasonably priced. However if you want to work with metal make sure the machine you're buying is designed for that. There are a few major differences between metal cutting and machines designed for wood or for additive processes (3D printers): The cutting forces with metal (...

3

I have never seen a stepper motor manufacturer not specify the torque vs. speed. I'm not sure where you've looked but a lot of people re-sell various random equipment to hobbyists without providing the same level of information. These graphs look like this one (source) The way you drive steppers has a large influence on their performance. The DC bus ...

3

Stepper motors are nasty little beasts and I don't like them. Actually, stepper motors are perfectly good as far as they go, but there are subtleties involved in selecting them and running them -- and I've had a couple of projects where the incorrect motor was chosen, then the problem of driving it was dumped unceremoniously in my lap. Given a stepper ...

3

In recent years, there is a surge in low-cost desktop-size home/DIY/High School level CNC, milling machine, router and 3D printers (common 3D motions parts, just the 'head' differs). Hundreds of companies do sell assembled unit and/or kits. I do not have hands-on experience on this myself and cannot offer solid help. But since many people make/buy/sell ...

2

I'm using a NEMA23 on my Y axis on my greatly frankensteined MendelMax. The bed was elongated to 350mm along with other upgrades, so I needed the bigger motor. It's running nice and cool at 26 volts on standard Pololu DRV8825 stepper motor controllers. Note however that CNC platforms and 3D printer platforms have only three things in common: X, Y, and Z ...

2

This is not a trivial problem to solve. Assuming your DXF file contains various primitives like tracks and pads drawn out, you need to create an algorithm which draws cuts around them, to end up with a PCB something like this: This is known as PCB isolation routing, and is in itself is non-trivial because (I assume) the tracks and pads will overlap in ...

2

I assume you know (or can figure out) how to parse the line objects in the dxf file, and can convert them to straight line operations in g-code. So the basic problem is how to order the operations to minimize time (which is the same as unnecessary travel). This sounds like a variant of the Travelling Salesman Problem. Except instead of visiting nodes, ...

2

LinuxCNC is a good example. A simpler example would be GRBL, which runs on Arduinos: https://github.com/grbl/grbl/wiki

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If you want to build something that more or less resembles CNC machine, and use a pen as a tool and draw some pictures, then you will probably be fine (as long as you can do programming and have a lot of patience to do calibration). Why is this not a common solution? Usually you want CNC to be precise and to have enough power to move a tool at reasonable ...

2

CNC controllers, in most cases, control rotary motion and the model of how this rotary motion is tranformed, by the mechanism attached to the motor, to a translational motion is implemented in the controller. You can use any method of transforming rotary motion to a linear motion as long as the model for it is pre-implemented in the CNC controller or you ...

2

This depends on the machine specifically and the software that is being used to drive it, as well as the work placement and holding for the particular cut. Remember, there are typically two different zeros, a machine zero and a work area zero. Typically the tool moves to machine zero before travelling to the work area zero and beginning the paths. This means ...

2

How does a controller translate a move x 20 units to moving the stepper x amount of steps and keep dimensional accuracy? If the CAD G-code says move 200 mm in the x direction, how to you translate the G-code to tell the stepper motor that 200 mm? The G-Code interpreter interprets the motion command. It applies some basic transformations on it to make sure ...

1

Short version, yes having an s-curve profile is beneficial for smoother and more accurate tracking. Longer version: For all real hardware systems I've worked with it has been important to use an internally consistent profile. By this I mean, the derivative of your profile needs to match your velocity and the derivative of your velocity profile needs to ...

1

Your question can be generalized as how to "convert: a CAD model to G-Code (or NC Code). Generally CAD is used to design parts and CAM (Computer Aided Manufacturing) software is used to design the manufacturing process for the part designed in the CAD tool. In some cases this is highly complex (e.g. for 5 axis milling) and in some cases this can be ...

1

We have a ShopBot at our Maker Space and have had a similar issue. In short, adjust the distance between your limit-switch trigger screws and your hard-stop. If your hard-stop is too far away from your limit-switch trigger screw and allows the magnetic limit-switch to disengage i.e. turn off after passing the limit switch the software encounters an ...

1

Arduino and RPI can take the role of control systems hardware. They are not what someone would call industrial grade (although, in some cases, they are used in industrial context). It is hard to define what industrial grade means, it is in many cases subjective, but here are some aspects which I think are mostly agreed upon: Hardware and Software ...

1

So there's a couple of things you need to go through when choosing the power supply for this application. Number one you need to differentiate between the driver capabilities and the motors requirements. Now the motor you have listed is no longer available on the website, but I found several motors on the website that are similar to what you have listed. ...

1

You can approximate the breakaway torque by considering static friction only. From the static friction coefficient of the lead screw (by knowing the maximum load on the spindle, coming from the application) you can calculate the static friction torque of the nut on the lead screw. You should do the same with all linear guides and/or bearings that you have ...

1

I suggest you look at the Marlin firmware for reprap 3d printers. Essentially it parses out lines of CNC code and identifies each of them as a command. The trickiest of these are the mutli-axis coordinated movements where multiple steppers are involved such as g3/g4 circle interpolate. The magic is in the timers and trig.

1

Okay, I feel really dumb now. Turns out my sine/cosine functions take radiant as input rather than degrees. As expected, the resulting transform matrix has "nice" values. Since my implementation and the other tool, which I checked the results with, both use rad as input. Consequentially I assumed the math was correct, which was false and resulted in odd ...

1

The answer is no! Even if you ask: Is any professional CNC machine, build for metal/plastics/wood cutting, capable of cutting tile? The answer is still no! You can try it. It will work in the beginning but the machine will be destroyed soon. Why? Stone cannot be cut, except soapstone. Stone machining consist of crushing/cracking/grinding, cutting is ...

1

After reviewing the Polulu Stepper Driver manual, I realized I was wiring stepper wires in wrong order. The controller pin labels are: 1A, 1B, 2A, 2B. The controller card's manual was saying 'use letters as pair' but it suppose to say 'use numbers as pair'. Everything works perfectly after correcting the wires.

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Here's the important thing to realize: While many want to size motors based on cutting forces, that approach will almost always leave you with a motor that's too weak for good performance. Cutting force is not the limiting factor the motor needs to overcome. Rather, the limiting factor will be acceleration. Your motors must produce enough torque to ...

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