[zafarsalam]

The CNC conversion project which was running for the last 8 months has finally finished. I am going to post photos and details about this project here. Here are the photos of the machine before and after the conversion. More photos to be posted later.

Zafar

[zafarsalam]

These are the specs we achieved with this retrofit.

X-axis travel - 1515 mm
X-axis rapid speed - 20,000 mm/min (radial arm)
Y-axis travel - 2035 mm
Y-axis rapid speed - 7,500 mm/min (bed installed on machine base)
Z-axis travel - 400 mm
Z-axis rapid speed - 3,000 mm/min (quill)
Repeatability for X and Y axes - 0.05 mm
Maximum load tested on Y axis - 2,500 kg

Used Mach3 with smooth stepper ethernet and arduino modbus. AC servo motors on all three axes. 5.5 kW on Y-axis, 3 kW on x-axis, 1 kW on Z axis.

[dblox]

Well done! I've often thought about doing something similar. Looks good

[zafarsalam]

Ok. This is how it started.

Customer want to convert their radial drill into CNC. They need to drill holes in medium carbon steel upto 1600 mm dia and upto 150 mm thickness. That's roughly 2.5 tons of weight and they want repeatability of 0.05 mm between holes with that. They have a low budget for this so can't go for a new CNC machine. The drill they want to retrofit is an Italian machine. Manufacturer in Italy says that this can't be done and offers them their new CNC model (budget constraint!).

Here is the photo.

[zafarsalam]

Came up with this initial design. Add a linear table to the base, this will be our Y-axis. Lock the radial arm at 90 degrees to the table and use it as X-axis. Now we have a cartesian coordinate system instead of polar for the radial drill. Put ball screws and servo motors on X and Y axis. Another set on Z-axis too on the quill. Next step will be to calculate and design the linear table, ball screws, bearing blocks, servo motors, their mounting on the machine etc., etc., etc.

[zafarsalam]

Ok now. The design is approved so we go onto the drawing board. The linear table is the first priority.

First we design it to be made from cast iron, machine and fit linear guides to it. Calculated cost exceeds customer's budget. Switch over to plan B. Search for an old planar base and table. Found one in a junk yard in Lahore.



Scrap the vertical columns, gantry, drive motor, gears, rack and other fittings. Ship the base and table to Gujranwala at Mr. Iftikhar's workshop. He is a manufacturer of shears and press brakes (BnC bending Cutting shearing Hudraulic machines) and helped me find this machine in Lahore.



Next step, find the ball screws.

[zafarsalam]

With the planer table procured and despatched we head on towards the drawing board again (which is actually an Autocad based PC with internet). Now this one is hard. How to get the size of a ball screw which won't buckle under the load. Remember, the job's weight can be upto 2.5 tons. The moving table itself weighs nearly 5 tons and is sliding on v-shaped guideways which are 3.5 meters long. Where do we start?

THK website gave us some figures to start with when we were desgning the table with linear guides. It suggested a ball screw of 50 mm dia with 6mm balls and 10mm pitch for the loads and speeds we selected. The weight of table was comparable to this one but again those were linear guides and this is V-guideways with cast iron sliding against cast iron. Ok, let's compare our structure with other machines close to this size and weight. Customer happens to have a horizontal boring mill with a 3 tons table sliding on box slides (see photo). The screw there is 50 mm too.



A 70 mm dia ball screw having 2.5 m travel is available in the local market in Lahore. That would do the job. Buy it and ship it to Gujranwala too. Screw and nut weighs almost 100 kg. Comparable to that a 40 mm screw would be enough for the X-axis as we could push the drill head on radial arm by hand when it's gears are disengaged. Buy it too and include it in the package.

5.5 kW AC servo motor and drive selected for Y-axis, 3 kW for the X-axis and 1 kW for Z. Shipped these to the customer.

Mr. Iftikhar in Gujranwala will now take care of the Y-table. He'll give the slides an overhaul and install the 70 mm ball scews on it. After that he'll make mountings for the 5.5 kW servo motor on it which we'll install when all this setup reaches the customer's location. Sounds simple? No, it wasn't. This we'll find in the next post.

[DareBee]

Congratulations on a very professional machine build.

My only other thought is that I would have strongly considered refurbishing that old Butler into your drilling machine.

[Khalid]

Congratulations on a very professional machine build.

My only other thought is that I would have strongly considered refurbishing that old Butler into your drilling machine.

You are right as Zafar suggested us to convert the Butler into CNC drill but as a part of agreement we want the 1600mm x 2000mm work area and butler only can give us 2000mm.
Moreover, installation of new heavy spindle on the butler would have another challenge.
Zafar may give you dozens more reasons

[zafarsalam]

After seeing the Butler Planer, I had suggested to the client to use the whole structure. That way we could have a true gantry dill. But as Khalid has indicated, this would have restricted us to the travel of x-axis between columns which was roughly 1200 mm. Also the project was approved with the approach defined earlier and it was a very tedious exercise to change that. It would have stretched the budget for the machine beyond customer's limits too.

The most important reason to abandon the Butler structure was the attachment of drill head to it. We learned later during the test stage of our machine that hydraulic locking of the drill head before starting to drill is very essential for drill accuracy. That would be very dificult to implement on the existing structure of Butler.

[zafarsalam]

Build Thread

I am back in Karachi after spending a week in Lahore and Gujranwala, an hour and a half flight from here. Informed the customer that the work is underway and we'll be able to deliver the planer stucture within a month's time.

Called Mr. Iftikhar two weeks later to get update on the progress of overhaul. His cell phone is off. Contacted his manager and he informed me that he is out of country on some business visits. Asked about the progress of our job and he says that he has no work instuctions on that. I get his number overseas and contact him there. He says that he'll be back soon and start working on our job. We are still within our job's time limit of 4 months, so no need to panic.

We start working on the control panel box and the servo motors' mounting fixtures for this job. Another customer's Turret Punch retrofit is underway in Karachi. He is fabricating control box for his machine. We request him to make 2 of those. The box arrives at our workshop in 2 weeks' time.

In Sadiqabad, where our client is, the summer time temperatures go up to 50 C (122 F) so a panel A/C is must for the drives and electronics. Inquired about industrial panel A/C's and again budget goes out the window. Decided upon installing compact window A/C unit in our panel. It is big enough to accomodate it.

[zafarsalam]

Build Thread

We are into third month of our project. Controller box is almost complete. Break out board assembled and tested, Arduino programmed, Smooth Stepper Ethernet installed on the Dell compact PC, LCD screen mounted with function buttons.



Check out the progress on the planer bed. Mr. Iftikhar is back from his business visits. A new project on retrofit of Turret Punch starts in Lahore. I go with my team there. A visit to Gujranwala is also underway. It is one hour's drive from Lahore. Another surprise is waiting for me in Gujranwala. The planer bed is still lying there untouched. It is summer time and also rainy season. Almost half of Pakistan is affected by worst floods in history. Add to it the ongoing power crisis in the country. The delay was inevitable. Time is running out for the project. Slight panic starts to creep in.

[zafarsalam]

Build Thread

We are entering the 6th month of the project. The deadline is extended for two months. Customer was kind enough to understand the extraordinary circumstances we are going through. They too were effected by the flooding at their fertilizer plant during this time.

I get the news from Mr. Iftikhar that the overhaul for planer bed is complete and they have installed the ball screw to it. He asks me to bring the servo motor along so that he can make its mounts too. This is good news. We are going to finish it in time eventually.

I prepare my team to go to the customer to install the X-axis ball scew and motors for X and Z axes along with the control box. They leave for Sadiqabad and I for Gujranwala. Sadiqabad is exactly halfway between Karachi and Gujranwala.

At Gujranwala our first task is to check the torque at the screw end with the table installed. Mr. Iftikhar has already arranged for a hand-wheel at one end of the screw to check the torque. Till now all the parts were selected on rough estimates. Let's see how it goes.

I need to check the screw alignment first. They don't have proper instruments to check these. Ok, let's try it as it is. We'll make the final alignment at customer's premesis. Tighten all the bolts, put the handwheel in place. Try to move it with bare hands. And it does! What a relief. It's bit tight and needs a strong man to give a few steady turns. But it moves. Now, hang a weight to the wheel handle to find the torque which can just move the table. Handwheel is 300 mm in dia. The starting torque calculated is 28 N-m.



Our motor is 35 N-m. It is decided to put a 2:1 reduction at the ball screw with timing pulleys and belt. This way we make sure it runs without putting too much strain on our motor and also with 2.5 tons extra load.

I order an end support for the radial arm to be made at Mr. Iftikhar's work shop. He starts the work to mount the 5.5 kW servo motor on the planer body. Mr. Iftikhar promises to ship the planar base and the end-support to Sadiqabad once he finishes the motor installation and the paint. I return to Sadiqabad to check the progress of X and Z axes stuff installation.

[Bloy2004]

Build Thread

We are into third month of our project. Controller box is almost complete. Break out board assembled and tested, Arduino programmed, Smooth Stepper Ethernet installed on the Dell compact PC, LCD screen mounted with function buttons.

Hi Zafar,
Does that Dell compact computer have integrated video? Or is there a separate video card attached in a PCI/PCI-e slot?
From my perspective, it looks integrated. If so, that is good to know as some computers don't play well with Mach3 if integrated.
I have a similar compact Dell sitting around and avoid it as a machine control computer due to the integrated video.
If it works even though with embedded video, I'll start playing with it.

Nice photo of you and Mr. Iftikhar!

Also, do you have photos of motor mounted down in the bed with reduction belt?
Thanks,
John M

[zafarsalam]

Hi Zafar,
Does that Dell compact computer have integrated video? Or is there a separate video card attached in a PCI/PCI-e slot?
From my perspective, it looks integrated. If so, that is good to know as some computers don't play well with Mach3 if integrated.
I have a similar compact Dell sitting around and avoid it as a machine control computer due to the integrated video.
If it works even though with embedded video, I'll start playing with it.

Nice photo of you and Mr. Iftikhar!

Also, do you have photos of motor mounted down in the bed with reduction belt?
Thanks,
John M

John,

This PC has an integrated video. In fact all the PC's I've used with Mach are with integrated videos. Even the ones running on PP too. Never gave me any trouble.

This one is with 1GB flash disk on which compact version of win xp is installed which is available at Dell website. 250 MB is still empty on it after installing Mach, Smooth Stepper, XBox 360, Screen sets etc.

[Bloy2004]

Thanks for those pictures!

Build Thread

Mr. Iftikhar promises to ship the planar base and the end-support to Sadiqabad once he finishes the motor installation and the paint.

Did someone record the shipping process? It seems like it would have been something to witness.

[zafarsalam]

Build Thread

I arrive at Sadiqabad to check the progress with the machine. My team has already removed the handwheel for Z-axis feed, installed timing pulley to it and put the 1 kW Servo in place with 1:2 timing pulley reduction. This one was easy and took just a few hours.



Installation of X-axis motor mount is still in progress. The alignment of the ball screw with the radial arm slide took longer than expected. The mounting brackets were to be fixed to cast iron, unmachined surfaces. First they tried to make the surface as flat as possible with angle grinders and then machined leveling plates which gave them the mounting surfaces parallel and perpendicular to the sliding faces. The levelling plates had to be machined 5-6 times to get it right. I did the final alignment of the screw myself and in the end it got aligned within 0.02 mm with the slides. Not bad!



After installing motors, we realized the toothed belt is skipping notches on the pulley. We happened to have the wrong standard of belt shipped from Karachi. Sadiqabad is a small town and we can't get timing belts of all sizes there. We'll have to get it either from Karachi or Lahore. Both are equally far away.

It is only 4 days left before the Eid vacations and the planar bed is on it's way to Sadiqabad from Gujranwala. They say that we will get it next day. We will have to return to Karachi for the vacations. It is decided that we'll put the planer bed in place on the machine when it arrives and then leave for Karachi. We come back a week later with the new timing belts and finish the job. Everybody's happy for heading home for the Eid and also for the end of the project is in sight. But another delay is waiting for us which we'll find the next day.

[zafarsalam]

Thanks for those pictures!

Did someone record the shipping process? It seems like it would have been something to witness.

Unfortunately not. His workshop is in a narrow lane in the old city. He told me that they move the bed and the table out of the shop separately and put them together on the truck. Unmount in Sadiqabad wasn't recorded either. By the time I got to the site they had already unmounted it with their fast and efficient cranes.

[zafarsalam]

Build Thread

The planer bed finally reaches the customer's premesis in Sadiqabad. And guess what, they weren't expecting it to be this big. I had sent them photos of it earlier and also it's weight. Maybe they were expecting something like this.



The radial drill machine bed is raised 330 mm from the ground. Since the shop floor was already 400 mm thick compacted concrete, we had planned to clamp the middle of the planer bed to the drill bed and support the hanging ends of the planer with steel I-beams in 4 places at the floor. The customer rejected this plan and decided to build a foundation on both sides of the drill. It is to be 600 mm deep in ground and 330 mm above it to reach the planer bed. There goes another month again till they design, dig and build the foundation. We wish them happy vacations and return to Karachi with them telling us that they will call us after setting the planer base up on the new foundation.

[zafarsalam]

Build Thread

Two weeks to go before the final deadline (which was revised to 8 months when we last left Sadiqabad). I get a call from customer that bed is placed on the new foundation and we can come over to finish it over. I prepare my team and leave for Sadiqabad again. 10 hours drive.

The bed is on the foundation, levelled and fastened. They are going to plaster the sides of foundation today. Masonry work won't stop us from doing light work on machine. We install the Z-axis motor with new belt and also put the X-axis motor in place.



Next day, the table is taken off the bed to install the auto-lubricating pump, it's pipes and nozzles. Mr. Nooruddin starts laying out wires for motors' encoder and power cables. Next task is to align the Y-axis screw.