Raptor 5: a Fully Iron CNC DIY

as always I apologize for my English if any word or phrase is not understood, in case if you have any doubts or questions please email me.

Apart solder some piece of metal when it happens, you believe it or not this was for me the first working experience with the iron in the construction of large objects...

So much effort how much satisfaction ...

After months of study and work the plans to build a fully iron CNC has come to an end and I think with some success.

From the first idea of the project was buzzing through my head a name that would honor him, I present the Raptor 5

if you understand the Italian on this page you will find the complete description of the project: http://mircoslepko.blogspot.it/2016/04/vi-presento-la-raptor-5.html

Gears, Rack & Pinion, the noise it makes and the aggressiveness that has shown in tests recalled a predator, a bird of prey so I wanted to call me Raptor 5.

But because the number 5?

why is the fifth cnc that I realize, because it has 5 engines on board because it is the time when I get up every morning to build it.

After 1 month of solid design and 3D modeling and especially without copying any existing prototype I made my own prototype calibrated on my needs.

I used to draw Rhino.

Yes, now are struggling with the realization of a new cnc, the fifth to be exact ...

This will be a real challenge for me because forsake my loved wood and will use only iron. In the past the unique experiences of welding I made the I.T.I.S Mechanics school but I think we can do it this time, the rest just stick of iron pieces;-))

The real problem is that I do not have equipment to work the iron so slowly I'm starting to buy it. I had an old welding electrode for the job but I preferred a wire welder (see in photo).

First I build the base so I made a selection of pieces and I made cut by CNC locksmith to ensure greater precision. Total cost of the iron for the base € 150

From a company that performs laser cutting I did cut all the plates. Total cost of 8mm thick plates € 90

I first clean all tubular iron with diluent to remove all traces of oil, then the various pieces prepared for welding by scraping the surface with the flexible bringing out the live iron and creating small bevels 45° to allow the solder bath to better penetrate between the pieces.

I positioned the 4 pieces of the first part of the frame of a linear plane and I put them in miter without the use of teams or other but simply with the most simple and efficient method, measuring the diagonals and correcting the angles a little at a time with small taps.

I am having finally found the perfect angles I gave of the welding spots to stop the pieces then I double-checked the diagonal.

After rechecking squaring other 10 times I started to make the first weld seams. It had been suggested that to prevent warpage of the pieces is always better to make opposing welding, eg. before the upper side then the lower then the right and finally left.

The first weld seams were not very beautiful but then after a bit of training I improved the technique.

Complete all welds first one side then the other until you have completed the first part of the basement.

I clean and draw all the welds with flexible and apply a cold zinc hand to protect the weld until I decide to paint the entire hotel.

I repeat the same operations for the other side of the base.

Now that the shoulders of the base are ready can do it is combine them with the remaining crosspieces being always attentive to the angles.

They place all helping with the clamps up to put the stand squarely always measuring the diagonals.

To correct squaring I used the belts with tensioners positioned between the farthest diagonal and pulling a little at a time I reached the perfect angles.

The base is now ready and squarely.

Confirm what you say around about the welding and deformation that the pieces undergo during this process and reiterate that the opposing welding greatly dampen this phenomenon.

Having never welded before so large structures I discover new things for me, I realized that when I was doing a weld the frame on the opposite side was out of square of about half a centimeter then doing a second cordon opposite the back frame in miter.

I completed all welding and measuring the diagonals of the base I have a half a millimeter difference so I can be happy for now.

Finally, I have prepared the plates 120 x 170 x 8 mm to be used as the base toe.

Each of the plates will have two holes diam. 12 mm inside of which will place of the M12 grains for focus adjustment in the bubble with the floor.

In the meantime I have ordered other materials to proceed with the next steps

SRB16 guides 1300 mm + 4 shaft for the short axis (€ 106.00 on Ebay by cnc-discount)

SRB16 guides 1600 mm + 4 shaft for the long axis (€ 120.00 on Ebay by cnc-discount)

N. 2 Tubular iron 100x100x1300 mm thick. 3 mm for the shoulders

Having designed all the components beforehand and fulfilled the roadmap is bearing fruit.

As designed I have cut off to the blacksmith two iron beams square section 100x100x1300 mm thick. 3mm on which I made the marks and holes needed for mounting the modules and from the parallel plates.

The beams have a series of holes in the upper part for the fixing of the guides, the lateral holes in order to access to the central fastening screws and the holes 12 mm in the lower part for anchoring to the base.

I have marked all the holes for fastening the guides SBR16 then I prepared an abutment fixed to L on the plane of the drill press to obtain a better alignment of the holes along the axis.

To avoid misalignment of the holes I tightened before the plates (which will welded to the base) to the rafters with screws and nuts M12 then I put them squarely on the base and given some welding point to block everything.

Two plates are provided with slots in order to correct any convergence of the guides and to have the, the parallelism control.

I mounted the guides SBR16 helping me with a key to keep magnetized with a neodymium magnet to stop the nut and washer.

P.S. The lateral holes on the shoulders just need to be able to enter with the key and tighten the nuts

Now remains to start assembling the trolleys that will slide along the shoulders just mounted. I started by welding two of the 8 mm plates that I had made cutting laser

For moving the axes this time I shall take the rack and pinion.

Why this choice?

3 reasons:

1. many cnc wood Professional using this system
2. Cheaper than the belts and probably easier to install
3. I like to experience new situations.

I chose to use the module 1.5 by installing directly on the shaft of the two engines Nema34 two pinions Z20.

I will purchase these components from my trusty provider www.atti.it.

Here yuo can find the technical specifications of pinions and racks.

A bit of theory for the calculation of the holding force of the motors Nema 34

quick summary calculations I had done on the transmission power, and I ask those who know more than I correct me if I'm wrong somewhere count:

Nema 34 12 Nm means that on a 1 cm arm strength (theoretical) sealing is 1200 N or better 122 Kg.

Considering that the pinion has a pitch diameter of 30 mm means that the arm is of 15 mm and should have about 120 Kg of theoretical maximum seal on the pinion teeth.

Suppose the motor nameplate data is not reliable, we add the fact that you have definitely friction and the engine running well below halving of its capacity (to stay on the safe side) its strength to decreasing it kept at 60 kg.

Having two engines should get about 120 Kg sealing.

I first turned two nuts M10 junction up to bring a cylindrical part diam. 12 mm. The cylindrical part must function as a rotation pin for the movable supports of the engines.

The pin will have to stay in the carriage shoulder seat (always 12 mm) and enter the mobile support of the engine.

Subsequently I will install a spring device for always keep in contact the pinion to the rack. The spring holder also compensate for any misalignment of the rack.

This mobile system will be very handy when you have the need to quickly release the motors and to liberate the bridge from transmitting to do maintenance, clean and grease the components.

Finally the rack will be mounted on 100x100 beam where the guides are mounted.

A rapid update of a first problem encountered (and solved) due to the deformation of a following the welding of the shoulder plate.

One of the two shoulders that I had soldered at 90 ° underwent a major deformation generating out of square 4mm.

Immediately after welding had double-checked the angles and it was perfect, but the next morning I found a complete cooling the surprise.

As you can see from the picture the 90 ° angle is lost and order to be restored, I had to work hard.

The only tools I had available were the presses carpenter and tried to make do as best I could. I did not believe they were so tenacious two-piece welded ...

I tried different combinations by placing the terminals in various ways.

Found the right combination of levers I gritted my terminal until you feel pain in my hands then I kept everything for 10 minutes but it did not do anything because the plates are returned to their initial position.

Then with a butane burner I warmed plates and especially the welds until they become red-hot. I maintained the flame for ten minutes and then I let it cool for 3 hours.

After removing the clamps the plates had maintained the position (or almost), from 4 mm initial Now there is only half a millimeter.

I do not know if what I have done has somehow weakened the welds but it was the only one that allowed me to replace the corner.

If anyone has any suggestions to me about it I will accept them willingly and I will treasure.

I did some calculations to figure out what to buy mechanical components.

Stepper motors + Electronics

I ordered on Ebay kit that includes:

• n. 3 Nema 34 motors 12 Nm cod. 85BYGH450C-060 single-shaft 6A 151mm (weight 5 kg)
• n. 3 Driver DQ860MA 7.8A
• n. 3 Power 350W, 60VDC, 5.8A
• n. 1 5-axis Breakout Board
• n. 1 cable LPT

Pinions and racks module 1.5 as mentioned I chose to couple the pinion directly to the motor shaft, risky choice in the opinion of some users but now the project has been defined and the plates are all already cut so if I were to become aware that the engines are struggling to move I will design the bridge again the plates to accommodate a new transmission ratio.

The seller where I bought the racks and pinions is www.atti.it, costs are contained, and the assortment of products is really good.

Unfortunately racks are sold at a fixed rate of 2 meters and served 2 pieces from 1300 and one from 1600 mm, so I had to buy 3 racks of 2 meters.

This is the material that I ordered from www.atti.it

• n. 3 Racks in Module 1.5 lugh steel. 2 mt.
• n. 3 Sprockets Steel module 1.5 Z20
• n. 3 Sprockets Steel module 1.5 Z26

Because I ordered 6 sprockets when I served only 3 z20?

I caught three more z26 to test the movement and the loss of power with 6 Teeth.

A pinion Z20 has the pitch diameter (dp) 30 mm whose pitch circle is 94.2 mm. This means that when the pinion will perform a full turn the axis of the CNC has made a shift of 94.2 mm.

Assuming to use the full-step motor (and thus 200 steps / rev) we have to divide the distance traveled of 94.2 mm / 200 = 0.471 mm steps (for each step will advance the axis of 0.471 mm), this means that the resolution of the machining It will be only about half a millimeter for which is too coarse. Then it goes will have to use the microstep.

Z axis choice

Perhaps a bit of laziness or to lighten a little the workload the Z axis I buy it already assembled.

I am doing the math than I would have spent to build it I became convinced that it was ready to take it the most economical and efficient solution.

Always on Ebay by cncgenius I bought this beautiful block of aluminum that will be mounted directly on the carriage of the bridge. It does not include the motor Nema 23 will buy later.

It has all the features I need: a ball screw Ø 16 5 mm pitch with flange nut precision class A: +/- 0.003mm the preloaded angular contact ball bearings mounted on the screw torque for zero axial clearance Shoes and round bars Ø20 Ball High accuracy without backlash. Drive in synchronous toothed belt on pair of pulleys 1: 1 Motor bracket Kress Ø43

Honestly some doubts about the success of the project because maybe I'm getting in the design phase could take some care more about a reduction ratio between the motor and pinion and the total weight of the bridge.

The pieces of the bridge are very heavy and added to the weight of the guides, the carriage, the Z-axis and electrospindle will do the weigh even more and I may have very high inertias. in addition the stepper motors vibrate excessively going into resonance, and these vibrations will be felt throughout the entire structure.

At this point I think it is the best finish the project and then evaluate any changes if necessary.

I cut the racks as the length of the shoulders (1300mm) and from these I soldered with an L-shaped profile of the slots to be able to fasten the assembly to the shoulder and adjust the alignment.

Sign of the holes on the shoulder in the slots. Note: the solution I've found to do the slots is to make 2 holes and then cut with a jigsaw with iron blade.

Mount the rack on the shoulder perfectly aligned with the guide is an enormous task for me so I welded behind the perforated strips to post an adjusting screw. The slots formed on the L profile will allow the rack to rotate slightly just enough to correct the alignment.

Now it's time to test whether the measures envisaged in the project have been met, he worried me the distance between the pinion and the shoulder wall that had to be about 2 mm.

What I remains to be done is a spring mechanism for slewing the engine block so as to keep it in contact with the rack in an elastic way.

I looked around to find a solution in order to put all the electronics of the CNC.
It must contain 5 DQ860MA driver, 5 power supplies and a control board.

Fortunately the company where I work was scrapped 3 web HP Rack 19" server2 units so I have been given, the beauty is that two of these are still perfectly worked so tickles me the idea to use one for the PC that will control the cnc.

For now I sacrifice one eliminating all internal things to make room for new components.

Some past flexible to remove the supports of the way and the box is ready to accommodate the new components and the server will have a second life;-)

Respecting the project I assembled the tubes and the 2 plates to make up the bridge as in the figure below

First, I got all the holes needed to mount the rails and the rack and then I joined with the soldering points of the tubular 60 x 60 x 1759 mm along with the plates.

Before continuing with the construction had the irrepressible need to know whether the engines would be able to move the bridge and, thing that worried me the most, if the vibrations were contained.

During the first free operation of stepper motors vibrations were so strong that I could not keep the engine in hand, it worried me greatly because of an iron structure is even more amplify.

I then prepared the CNC in order to make the first tests. In practice, the coupling of the pinion with the rack should not be fixed but elastic for 2 reasons, one to compensate for any misalignment of the rack and two to dampen a little vibration.

I soldered two L profiles face to face one to the movable plate (which supports the motor steper) and the other to the shoulder.

I drilled them to be able to insert a screw M10 that will unite them in a flexible way through a robust spring. The spring I bought at the hardware store and then cut adapting it to run required.

Finally I loaded the spring and verified the coupling elasticity.

I plugged in the box 5 driver for motors, the control board DB25-1205 and 4 12-volt power supplies.

I had previously welded to the old web server rack chassis 19 of the L-shaped brackets for fixing the driver and power supply units.

The bridge of CNC will be driven by two motors.

I connected the right engine to the pins of the Y axis tab and the left engine to the axle pin B, then I illustrate with a pattern wiring and mach3 configurations.

Mach3 has a special function to use two engines on a single axis is called "slave" where you have to choose how stepper motor will have to be the "slave" of the primary stepper motor. In my case the axis flowing the bridge Y is why in mach3 I set the B-axis motor shall be servant (slave) axis Y.

I gave power to the stepper motor, configured on the microstep driver and step in Mach3 configuration calculating initially grossly on the pitch diameter of the drive pinion.

From the first movements motor stepper went into resonance, really strong vibrating, all bolts of the bridge had loose advancements, the floor vibrated as if outside my house was falling apart a building ... not very well ...

I tried all of microstep configurations and different acceleration and speed settings but in vain, under 400mm / min completely silent then increasing the speed engines were increasingly resonate. I had read that at low speeds the larger stepper motors went into resonance before the smaller, then, after the critical speed of the motors to operate sulenziosi resumed.

I was two days to think with the anxiety of having to review the entire distribution considering replacing the racks with ball screws...

Then in desperation I tried another way by reducing the amps on the driver, and then de-powering the engines and I find that the vibrations were in dropping down to a sustainable condition at the expense of a drastic reduction of the current two-thirds (2/3) of I brought 6A to 2A and everything is miraculously improved.

Obviously engines with less power also lower torque sealing so I did a very scientific test ... I literally leaning weight to the bridge of the CNC while the engines were advancing but I could not stop them. Even with less power the stepper motors were able to work. Then I adjusted the parameters of speed and acceleration of further improving the situation.

This does not mean that the CNC is perfectly silent and vibration-but at least I avoid is disassembled while working or worse than moves the other side of the lab ....

Fixed issue vibration I started to mount SRB16 guides on the bridge and the truck.

The parallelism has been relatively easy to fix because the holes I had done previously to my fortune were well aligned. I had them made simply by mounting the drill press a fixed stop.

Then I soldered a 1680 mm rack on a thick strap iron. 4mm on which I made the slots to allow better the parallelism with the rails.

List below the various components

• 1 x Control Board Breakout Board DB25-1205
• 3 x DQ860MA Driver to operate in Nema 34 motors
• 2 x Nema 34 (axis Y + B axis slave - bridge)
• 1 x Nema 34 (X-axis)
• 2 x DQ542MA Driver to operate in Nema 23 motors Nema
• 1 x 23 (Z axis)
• 1 x Nema 23 (4th rotary axis)

Among the pictures I uploaded in this step you will find the wiring diagram

In Mach3 the first thing I did was set up the pins of engines according to the diagram I drew.
The pins that are read on the breakout board just exactly the ones that should be set in the mask. Configuring the motor pin: Menu -> Configuration -> Port and Pins -> Motor Output

With the wiring I have adopted the values Step Low Active must be enabled. I have not found much documentation about it but with these values enabled the engines run more smoothly, probably because I connected step and say the driver of the negative pole (but I'm not too sure).

The parameter Dir Low Active should be used to change the direction of rotation to the stepper motoer then being the two opposing bridge engines one of them has to turn in the opposite direction so as you can see in the picture above I activated Dir Low Active axis B

Configuring the second engine of the bridge (slave)
I had to specify that the axis B is the second setteper motor of the bridge (Y axis), and to do this on mach3 in Slave Axis section, and I set the B axis as slave axis Y. Menu -> Config -> slave Axis

This is just the start of configuring Mach3, then you need to set the steps of the motors, the accelerations and other parameters useful for a correct operation. Provisionally I calculated theoretically based upon the step of:

pitch diameter of the pinion of the rack 30 mm

microstepping 1/16

pitch circle 30 * 3.14 = 94.2 mm

Number of stepping motor 200 * 16 = 3200

Resolution 94.2 / 3200 = 0029 mm

Step for 1 mm Feed stroke 1 / 0.029 = 34.48 step

N.B. this configuration might be changed until the time when I will have not tested all the behavior of the CNC.

Meanwhile I had to make a change to the rack of the bridge because the solder had slightly curved in some places and so it was not all planar points.

I soldered on the bridge ten tie rods formed by a profile "L" 30x30 mm and on the rack in correspondence of M8 nuts to be able to insert M8 screws and calibrate the linearity.

The vibrations, though much reduced, are still present and I would like to take all necessary measures to minimize them.

Surely I will follow the advice a reader filling the tubular with foam then at the points where they are bolted some critical components (racks, bridge and plates) anti-vibration rubber insert of the special, the one I already used for the machine feet.

I wired the electrical box controls and mounted the arms to the CNC to house all the electronics (computer drives and Box).

With the availability of 3 Server HP DL380 G4 Rack 19" am I try to use one with Window XP then to be able to use as a computer because it has 6 GB of RAM and dual-processor Xeon 3GHz. The only real problem is that it does not have a parallel port and PCI slots but only PCI-X 3.3 Volts. I bought a PCI-X 3.3 Volt board but the breakout board wants mandatory 5Volt to properly handle the PWM signals and then I had to shelve the idea.

In the photos you will notice the electrical control panel with which I will give power to all machine components: PC, control board, drives, inverter spindle, spindle cooling water pump. I have set up a main switch and an emergency button.

the Z axis that I bought has a connection for the Kress but I chose not to use the Kress but to buy an electric inverter cooled liquid to 2.2Kw.

Included is practically everything:

• Electrospindle inverter
• Support bracket
• Water pipe
• Water pump
• Wrench to tighten
• 13 for milling collets from 1mm to 13mm

I had to only fix the stepper motor to the Z axis and build a support bracket for the electrospindle

I decided to do things right and this time I do not miss anything !!

I then sealed the swivel arms where to place us monitor, keyboard + mouse, inverters and electrical control box.

In the left arm there will stand theinverter and the electrical control panel while im the right part of the human interface.

I did cut the tubular 50x50 to the blacksmith and the cylinders that I will use as a hinge.

I got the seats for the cylinders and joined the pieces as designed.

Now we must do the electrical wiring and the installation of accessories such as cable glands chains, electrical boxes the monitor port and keyboard, and so on.

I will not dwell too much to explain how I mounted the fairlead chain because it does not require special care because they do not come cheap but the advice I can give is to buy them as short as possible doing good terms with the minimum bending radius and the distance from cover.

If, as in my case, the axis is 170 cm along the length of the chain is only because of 1mt positioned in the center it is able to cover the whole travel.

If you have had a look on Ebay you will have noticed that these glands chains are not exactly cheap, for a measurement of my chain meter you can get to spend up to 100 Euros. Fortunately I bought them used to 30 €

After about a week of study and research I realized how to connect the inverter that drives the spindle.

I must say that the manual is too technical for those who are beginners and do not know the operation of these toys. At my own risk I tried wiring and apparently all went well (for now).

The control of the electrospindle rotation speed is managed by Mach3 but not through the breakout board but on RS485 interface.

Said more simply Mach3 (after installing a special plug) can communicate with the inverter via the serial port with only 2-wire RS + and RS.

it will be necessary to have a USB to RS485 converter that you can easily find on Ebay 5 Euros like this below.

At the end of the game the two-pin adapter will be connected to the inverter pins labeled RS + RS.

As I said before you have to install a plugin on Mach3 available from the website of a French who developed it and explains well how to make it work.

The PC that I am currently using is very dated and I have a problem with the USB ports, it seems that does not have the USB2.0 and I can not find the mainboard chipset drivers.
In fact, when Mach3 launch a command to turn the spindle USB ports stop working and I lose the mouse and keyboard. I solved the problem by installing a USB 2.0 PCI card

My spindle is cooled liquid is then I connected the water pump to the inverter.

Reading the inverter documentation I find that, in addition to being equipped with hundreds of functions, you can program it to make him drive a relay at the time of the start and the pins of the relay on the inverter are marked with the initials FA, FB, FC. To these pins I connected to a 220 volt plug that will use it to power the water pump.

I finally completed the monitor stand, keyboard and mouse; the computer being positioned on the opposite side of the cnc I had to make up a VGA cable and a USB to 5 mt.

Finally I turned on all the components and made the first milling.

At first glance, everything seems to work perfectly, there are still some software adjustments to do, but as a first approach are satisfied.

Previous calculations of the steps I had done it based on the pitch diameter of the pinion were correct in fact the movements are precise to the millimeter, then I'll do a calibration of the axes to achieve a higher accuracy.

I simply routing a circle inside a square, and the first impression is a nice clean cut.
the spindle is very silent and vibration are contained

Mount the limit switch is not complicated and instead of mounting the ends of the machine I placed them on carts to run as little as possible along the machine with cables.
I connected the limit switches to the emergency stop so you never exceed the maximum limits and risk damaging collisions, then will place the other 3 switches to manage the homing.

The ends of the cnc I mounted instead of adjustable stops.

Before deciding how to achieve the milling plane I thought to tens of solutions that allowed me to have stability in addition to the possibility to configure it according to the requirements.

First I would like not to have a work plan closed because in my previous experiences, I realized that all machining chips piled on the floor made it difficult to remove them and obstructing me the threaded holes for fastening the piece locking clamps.

Having said that the work plan must be open and allow the chips to fall to the ground, another thing I wanted was not a fixed plan is not removable because if I find myself to do work on very high pieces I would be prevented.

Maintaining the concentration of these two objectives I have come to the conclusion that the best solution is to mount a series of parallel beams bolted to the Y axis Above the beams will set the 100x100 mm blocks equidistant solid wood forming a kind of chessboard.

To support the beams to the structure I soldered to the inner ends of the frame of the L-profiles ..

The preparation of the 10 beams was long and laborious because I drilled them to fix the elements of wood.

On each beam I got 20 holes diam. 6mm loops (so 40 in total per beam) so I had to make the beauty of 400 holes, a monkey's job ...

After all beams bolted to the structure I prepared the blocks above to apply ourselves.

I used the WPC (Wood Polymer Composite) which in practice are the staves in composite material that is used for outdoor pavings.

For now I bought a single rod 3 m (30 euro ...) and I got so many pieces 90mm which I then drilled to accommodate the holes of the beams.

Now before you complete the assembly have to prepare the CNC for painting.

Dismantle all cnc makes me cry my heart because it is already calibrated and square and I get a little tedious having to reassemble and recalibrate.

Thus, in 5 hours I removed all components and sanded the various pieces.

I will proceed with two coats of rust and two coats of paint, the base will be done with a brush to the inability to use the compressor in the carpentry shop at the risk of creating a dust and sawdust storm, all the other pieces will bring them to the outside spray.

I make a short step back to explain the solution I have adopted to integrate the fourth rotary axis to CNC.

My initial idea was to always have the free work plan but to have the fourth axis ready for use, so I opted to mount it on a hinge system that would allow me to hide it if not necessary.

I mounted at the point where the machine would give less discomfort to the side on the front.

But we come to the procedure of implementation ....

With welded rectangular tubular between them I made the base on which I mounted the aluminum profiles for the rotary axis attachment that I had already built a few years ago.

Then, with two profiled cutouts "L" I got the supports for securing to the machine with the hinge mechanism.

On board I made 4 holes at the fourth axis supports and I assembled everything.

The slots cut on the media to "L" I will serve for better parallelism.

Now the fateful moment, painting ...

Paint is not an activity that I particularly like, the preparation of the pieces is long, laborious, I have little experience and is always the fear of doing damage, leakage, burrs, etc ...

The father of my wife I had a favor so I asked him to give me a help because he has worked for 30 years in the paint shop of 'SCM Rimini which produces machinery for wood: who better than he could help me?

Premise

I chose two colors that were well matched and that they could hide the dust: gray cement and acid green. I had prepared the two colors from a paint store near my house; I chose the colors from the catalog and I was assured that the color would respect the champion and I have blindly trusted ..........

On Sundays I opened the jar of green acid and saw an ugly color but so ugly that compares a dirty diaper (of a 1 month baby) would be more pleasing to the eye. But as I prepared everything I did not want to spend another week and having to rewash all the pieces I still decided to use the same; probably I'll regret.

The stand not being able to move everything was done with a brush while the rest of the pieces outside compressor; before a generous coat of rust inhibitor for body and after 24 the paint.

Having said that I explain how I spent the weekend getting drunk with the Nitro thinner fumes and the powder coating, an experience that I would not repeat.

Preparation and cleaning of the pieces

All parts have been thoroughly cleaned with Nitro-Dilution (brush and cloth) to remove all traces of grease and dirt and all the abundant streams of cold zinc (of which I was very proud) I due to sand because it would compromise the seal of the paint: - (((((.

I do not hide that this experience as marked me, I'm not used to breathe all those vapors, I had a headache for the whole weekend and the color result was not as hoped.

The only positive aspect is that at least the rust has been given and no more dirty iron hands black as before.

Now I will have to reassemble the whole CNC.

Finally the end is near ...

As usual, I tried to document everything and I also made a video timelapse to live again the experience

Reassemble everything led me away anyway 18 hours of work and many hours of sleep.

A very useful accessory that could not miss, and I had already made for my old cnc is the illuminator LED placed under the electrospindle.

When used it can not do without especially if the laboratory is poorly lit.

My spindle has a diameter of 80 mm so I milled a kind of nut that could go to joint without having to use glue or other gadgets.

I created a tool path drawing the frame with a diameter of 80.2 mm and must say it fits perfectly.

The LED ring to be fed to 12 volts this time I bought it ready on ebay about 10 euro.

I still remember like it was yesterday when at school we did in the laboratory exercises with pneumatic pistons.
I always wondered if one day I could serve a pneumatic system .... and yet never say never.

If during the lessons I had been more interested in the subject now I do not find myself with some doubt / difficulty using the valves.

In any case I do not think it's a difficult thing, and for the moment I concentrate on the mechanics of the tire then wiring in some way I will.

I bought used a block of 8 Festo ADVU 32-50-PA pneumatic pistons and various accessories, valves, fittings, hose to just over 100 Euros, a good deal !!!

The idea is to build the devices for the clamping and release of the pieces more easily than traditional screw systems and bracket.

I have 7 large pistons + 1 small and I would like to build some for work in a vertical way to press the workpiece against the plan and other horizontally to push the piece against the jokes that always will place on the plane.

Design

Designing a first prototype beta I made with lego my son and I do not hide that it is not the first time that I take inspiration from the famous bricks.

This prototype works in vertical and presses the piece on the working plane.

For now I have not a pneumatic system so I tried the pistons with the compressor gun

I discover with great surprise that they have an incredible force, then if I apply a long lever principle could increase even more its power.

According to the rating data these pistons can develop a force of 50kg and since the prototype I built has slightly long lever can perhaps even reach 60Kg.

I leave you video of the tests I did.

I have also developed a prototype, perhaps most practical and easy to install that instead of having the vertical piston has it horizontally and then is adaptable in most situations.

For the construction I always used iron straps and some piece of the T-profile and the fork to be applied to the piston I made from a rectangular cut into 2 parts tubular.

The good results encouraged me to achieve the other seven devices.

After building the clamps of the pieces I've equipped the cnc of a small pneumatic system to handle 3 types of devices

a blowing gun a refrigerant liquid atomizer clamping system of the pieces to be milled

The plant is composed of

• 2 pressure regulators with pressure gauge
• 1 to 2 positions valve for controlling the pistons
• 1 blower spray coolant
• Several meters of pipe to 6mm and 8mm
• Various joints and fittings

Placement of fasteners

To quickly lock the clamps I put to each of them a rapier system that hooks the blocks placed on the work surface, this way I can quickly orient the pistons without having to continually pick up the keys to loosen and tighten.

The high pressure exerted by the piston was sinking into the part of the screw heads so I had to replace them with rubber bands

For cooling the drill mounting the blower side of the spindle and
fed with compressed air.

The blower during the passage of air suction from a rubber tube to the venturi effect of the fluid that will be sprayed onto removing heat cutter and chips of the way. The jet of the breath is controlled by the second pressure reducer on the machine.

Caution
As I was rightly pointed out by a much more experienced player than me I would like to make a clarification, using pneumatic pistons it is simple but also dangerous because if during processing lowers the air pressure tightness of the locking systems may be compromised and it follows that if the piece moves you could make sure that the cutter may break or worse splashed away splinters threatening to hurt someone.

Having said that I simply illustrate the work I've done but I do not take the responsibility if someone gets hurt

This type of problem can occur with the use of compressors with small tanks. I made the choice to adopt the pneumatic system because aware that my compressor would be able to maintain a consistently high pressure as it is of those industrial designs with a large donut 80 cm and 2 mt. high I do not know how many liters is big but it's nice so I think to be safe.

For those who speak Italian in this page you will find the complete description of the project: http://mircoslepko.blogspot.it/2016/04/vi-presento-la-raptor-5.html

If something is not understandable please let me know
thanks for reading.