Usefull information before you build a Raw 1.5 CNC machine

This article will go through the whole machine and the different options. You can choose to build your machine with parts from us or others and have different type of electronics and drive systems, let’s go through it all.

The first thing you need to do is to decide what type of machine you are building. Raw 1.5 comes in different versions.

  1. Raw 1.5 with timing belt and pulleys
  2. Raw 1.5 with Racks and pinions
  3. Raw 1.5 with Ball screw
  4. Raw 1.5 Extended with Ball screw
  5. Raw 1.5 Extended with Racks and pinions

Raw 1.5 standard model is a 990x990mm machine with belt, racks or ball screw. Raw 1.5 Extended is the longer version of a raw machine and has racks or ball screw as the only alternative.

Timing belt and pulleys (For standard raw 1.5)

Raw with timing belt and pulleys. The machine is designed to use 15mm wide belts with 12-20 teeth pulleys. Timing belt can be good or bad depending on how you use them. I have seen many projects that builds CNC machines with a G2 timing belt that is 6mm wide. These are like rubber bands and are only suitable for 3D printers, decal and paper cutting machines. The backlash with a 6mm belt must be brutal. I use timing belts for my machines as well but these are HTD3M belts 15mm wide and with a steel core. These work very well and you can even turn the belt upside down to avoid dirt. I like belts, they are cheap and easy to replace. As with the rack you will get speed and strength and very good accuracy. I recommend you to use belts for your first machine.  Belt machines runs smoother than a rack machine and I usually recommend timing belt before racks for machines under 1 meter.

 

  • Protection against dirt = Very good
  • Backlash/Accuracy = Very Good (with wide belts and machines under 100cm)
  • Speed = Very fast

Racks and pinions (For standard raw 1.5 and Extended)

Raw 1.5 and Extended. The machine is designed to use MOD1 racks with 12-16 teeth pinions. Racks makes the machine stronger and has less backlash than belt. With racks you will get maximum speeds with enormous powers. This is the dream option for you who really want to work with your machine. On our Raw 1.5 machine we have racks as an alternative. To make the construction as cheap as possible, the rack hangs outside the machine and up side down to prevent dirt from getting caught in the teeth. The advantage of this is that we do not need a mechanism that forces the gearwheel against the rod, a Raw uses gravity to handle this for us. Many have questioned this idea, but my tests show that this works ridiculously well and are extremely easy to construct. Check our videos if you are in doubt. One disadvantage of a rack is the sound and vibrations when you jog the machine back and forth. We do not want to lubricate racks in a dusty environment, so it’s steel against steel, but this does not affect the cutting results if you cut in wood or material that dont require extreme accuracy. If you need accuracy then read about ball screw below.

  • Protection against dirt = Very good (probably the best solution)
  • Backlash/Accuracy = Good (If you find high quality pinions)
  • Speed = Very fast

Ball screw (For standard raw 1.5 and Extended)
Ballscrew is the latest addon to the machines and are the option that has the best accuracy. The disadvantage with ball screw is that the machine is slower than belt or racks. It’s also recommended to use stronger electronics like the driver option that we have instead of Arduino. You can use Arduino, but the machine gets painfully slow. The machine is designed to use 1605 – 1610 ball screw (16mm I diameter and 5-10 mm per revolution) 16mm Ball screw is best for machines under 120cm in length or width. You can use 16mm ball screw on longer machines but usually you will go up in dimension to maybe 20mm. The machine is not designed to use 20mm screw, but you can modify the plates to accept that. We are not responsible for any modifications.

  • Protection against dirt = Very good (If you have the Screw outside or behind the machine like we do)
  • Backlash/Accuracy = Very good (probably the best solution)
  • Speed = Slowest option
You need high quality gears/Pinions!
A machine with a rack drive requires top quality gears. If you buy gears/pinions from various online stores, they will be in such poor quality that the machine sounds and vibrates. We have been searching for gears that are grinded (hobbing) 3 times or more and these are included in the hardware packages we sell at our shop. The gears come from a Swedish company and are very expensive and not like the others you find out there. The rack, on the other hand, is usually the same everywhere. Even with good gears/pinions, a rack machine has a mechanical sound since it’s steel against steel without lubrication. The sound does not affect the cutting results.

Plates and hardware
The second thing required is the hardware and plates. When you have the plates and hardware you can start building the machine. The machine is built with Metric screws and measures. We have had customers who has sucsessfylly built the machine with non metric screws, just stay as close to the original sizes and you will be fine.

Aluminum profiles
As a non-European it might be difficult to find the same Aluminum profiles we use over here. The measures are 20×20 up to 20x80mm. If you can’t find standard aluminum profiles you can use the Open build profiles with a V-slot, found at Openbuilds.com, While you are over there you can also see a tutorial of the Raw machine sent in by a user: https://openbuilds.com/builds/rawcnc-1-5-desktop-edition.5771/ . Instead of shaft clamps you can glue the rods directly in to the slot or groove.  This can also be done with standard profiles and the result is actually better than with shaft clamps. We have not tested the open build profiles, but it it has wider slots around 6.7mm, the steel rod that we use is 6mm but for V-slots you probably need 8mm shaft and 8mm U-groove bearings. We are not responsible for any modifications so its up to you if you want to do it this way.

If you decide to glue the shafts directly in to the slot, this is how it’s done.
As seen in the pictures we use silicon to glue the shafts in to the slots. This works if the shafts are clean from dirt and grease. Use other profiles to press the rod down as seen in the picture. Let it dry for 24 hours and you are done. Our machines are made this way to test the solution and they have been running daily for over a year without any issues at all. The only modification needed is to make the lower bearing holes on the plates a bit longer, just use a file to make the holes 3mm longer. You will understand when you tighten the bearings. Silicon is good since its flexible and wont crack like regular glue.

Electronics
Once the machine frame is built its time for the scary part…   ThE ElectRoniCs….
Sounds scary, but its simple, especially with our instructions. Don’t worry about that, just follow along. We have worked hard to make this as easy as possible with video instructions and illustrations.

What electronics do i need?
There are basically two types of electronics, one modern that uses USB ports and an older version that we prefer that uses the good old printer port. There is many different electronics, but we use these for Raw 1.5. You can use any electronics you like if it’s for nema 23 motors. Let’s break it down.


Arduino+CNC shield elektronics

Arduino with CNC shield is a simpler version of CNC electronics and can be used with any computer that has a USB port. These electronics has some limitations, such as handling multiple switches and zeroing plates found on our other machines. You can do well without these features if you only cut from time to time. Arduino cannot handle 2 switches at the same time, so it is not possible to calibrate the machine 90 degrees at startup, but it is easy to do it manually. It is usually this kind of electronics that comes with other DIY kits on the market.

CNC shield is not capable of having an advanced touch-off plate (Zeroing plate), so you have to start the machine from the surface of the material you cut, which is the way most people work anyway. Touch-off plate is a feature that is not needed, and you can do well without it. If you want a more advanced machine, look at Driver Electronics. You can also upgrade your electronics afterwards if you notice that you need a more advanced machine. Any upgrading requires upgrading of motors and other electronics.

Driver elektronics

Drivers with Breakout Board are the most professional electronics you can have for these types of machines. They are more expensive and require an older computer with printer port and 32Bit Windows operating system (if you run Mach3 software)

Some of the benefits of drivers are that the machine gets much stronger and has many more features like advanced touch-off plate (reset plate), calibration switches, on and off spindle, laser and plasma functions. The range of software is much larger, and you can also use software that the industry uses.

If you choose Driver Electronics, you will be able to calibrate your machine so that it starts at 90-degree angle and you can also have an advanced touch off plate that we offer as a separate product or you can make your own. Read here what you need to run drivers electronics http://rawcnc.com/set-up-mach-3/

You can look at our website which drivers we use.

Driver electronics with USB
We have tried all kind of USB electronics with drivers and there is only one that works. Look at the product UC100

You will find more information about the electronics when you build the machine.

Steel reinforcements
You can make a Raw machine even stronger by adding steel to the Y and A axis as well as for the X-axis. We recommend adding a 60x40x2-3mm tube as standard to the X axis as seen in the instructions. To reinforce the Y and A axis with a Steel angle bar is optional. This is not needed for smaller machines, but it makes the machine even stronger. We have Steel upgrades as a product on the homepage or buy 40x40x3-4mm angle bar locally. You can make a Raw machine even stronger than that by filling the aluminum bars with epoxy or thin concrete, this will make the machine ridiculously rigid and close to a steel machine.

After the machine is built you need to configure the software. Go to our article section and read the instructions on how to set up Mach3 or Estlcam or use other software you know of.

Example of the video instructions that can be found on Youtube and our site along with the illustrations.

This is from a customer who is cutting a branding iron from copper. The user is CNCswede and you can find him and his work on Youtube.

Cutting a fidget spinner