Often times CNC programming tutorials only teach you how to create the tool-paths and not enough attention is paid on showing how to properly hold parts being machined.
At the same time efficient workholding is an art in it self and mastering it could drastically improve shop productivity and accuracy.
Without further ado let's jump into the workflow.
Step 1. Analyze the Drawing and the Model
We would have to look at the drawing, tolerances and the CAD model to develop the machining strategy.
This particular part has tight (+/- 0.001) tolerances between the features located on the top and the bottom sides. In addition to that it has a 2.5 degree draft angle on external walls.
Thus I decided to not use the soft jaws approach and machine it in a fixture. Soft jaws are generally OK for tolerances down to +/-0.001" but because of the draft angle the part would always want to pop out of the jaws.
Before we start milling away our stock we first need to get down to the required depth.
This is not a problem with external features when we can plunge outside.
When machining closed pockets, however, we need to find a way to get down to the machining depth first.
As usual there are several ways to get the job done. The plunging methods listed here are not ordered by their preference.
For various machining operations on different materials some may be more preferable than others.
Straight Plunging into a larger Pre-Drilled hole
This is one the best ones in my opinion. Very few machining modes can compete in effectiveness with drilling and this method will get you the best combined tool life on most materials and (in case of many deep pockets) the least machining time, even when tool change time is factored in.
January 23, 2017, 12:41 am by Eldar Gerfanov (Admin)
Check this out, guys.
Been working on this for the past couple of weeks:
New FSWizard Speeds and Feeds Calc will have not only modern improved design. But latest tools and materials. Special attention is being paid to have it produce EXACTLY the same results as our HSMAdvisor desktop app.
It is not complete yet, but it is almost there - making it catch up to the latest HSMAdvisor code is a big job.
The new calculator will replace our online calculator as well.....
Yes, you heard that right! You will be able to run exactly the same FSWizard Speed and Feed calc on your mobile phone, desktop and even Windows Mobile.
Heck, it will even work on Mac!
Best of all, it will be published as an update to our existing apps, so our existing customers will not have to buy an upgrade, unlike what some other "Machinist Calculator" has done in the past.
This is 21st century and we all live in the age of the Internet.
While some software developers claim to use it for the benefit of the customers they in fact only care about license protection benefits it can provide.
Tool Database and Cutting Data Sharing Not many users realise that simply placing the Tool Data Base file on a shared network drive or service like DropBox or Google Drive will keep their Tool DB in sync on all of their computers running HSMAdvisor. Oh, regarding the "running on multiple computers" thing.....
Floating License allows users to run a single seat of HSMAdvisor on multiple computers non concurrently. All you need is internet connection! Permanent Licenses do not even need internet connection at all.
Cloud-Hosted Machine Profiles. Machine Profiles are important part of out calculator tool. Among other things they allow to prevent machine stalls and resulting machine damage and tool breakage. You can upload your Machine Profiles to HSMAdvisor Cloud for Public or Private access. Or you can request a machine profile to be added and I will upload it for you to easily download. All within the HSMAdvisor Machine Definition dialog!
Cut Cloud. The place to get other Machinist's experience at your fingertips. Another great feature that we are actively developing right now is the Cut Cloud. It allows Machinists to share their cutting experience with other HSMAdvisor users. It is still in development but shortly we are going to populate out public online library (Cut Cloud) with cutting data from popular tool manufacturers. Anyone running HSMAdvisor will be able to just dial in their cutting tool, connect to the Cloud and see how others run their tools in similar cutting conditions on similar machines.
Immediate and Accurate Licensing. A few times I got emails from disappointed machinists who were not aware of HSMAdvisor and thus chose a competing software product. They all were complaining about misleading Licensing schemes some software developers were using that hindered their work. Things ranged from not being able to register their seats for hours after completing the purchase to having to keep their computers online almost uninterruptedly (despite claims it could run offline for weeks) to keep their software running. HSMAdvisor uses transparent Permanent and Floating Licensing scheme that will not leave you hanging. All purchases are handled automatically and our new customers do not need to wait for a next business day to get their purchase functioning. We constantly work on making your experience as flawless as possible and do not linger on past achievements.
There is a lot more work planned and already in progress.
In the age when everyone is talking about how internet is turning the world around we are doing our small part in making it happen!
Thank you, everybody for your support and feedback!
February 27, 2016, 1:21 pm by Eldar Gerfanov (Admin)
Being a CNC Machinist/Programmer is sometimes more than simply creating a program and machining the actual part, often times it is about creating efficient and accurate fixturing.
In this little project:
I had to machine rectangular cut-outs and drill holes through an already-turned steel ring. Then I had to part each ring to 4 equal pieces.
There were about 100 such rings that worked out to 400 pieces in total.
After drilling holes on an indexer I had to machine a fixture to hold my part through 2 remaining set-ups.
First half of the fixture consists of the expanding mandrel:
The work-piece would be mounted on it like so. A hole on the side is used to properly position it:
February 27, 2016, 12:06 pm by Eldar Gerfanov (Admin)
Being a professional CNC Machinist myself with a good manual background I often find myself watching various machining videos and blogs.
Unlike others I do not often share somebody-else's work, I could just not walk past this one and not tell everybody how great I think this is....
This story was posted on "Russian reddit" and here is the direct translation of the author's post:
Quote:
We have a mechanic/installer at our work. He used to be a lathe machinist on a previous job and had a hobby - created a model copy of KrAZ-255B military truck. Right now he does not have time to work on it but is planning to return to it once he has more time on his hands.
Here is the mid-way result of his....art!
Lets begin with tyres. Vladimir (guy's name) decided to create the mould to make the rubber tyres himself. Here it is:
Here are the tyres he made with it. Beautiful aren't they?
He also made little differentials. Housings, gears. Everything made himself:
September 19, 2014, 10:23 pm by Eldar Gerfanov (Admin)
In the latest update to HSMAdvisor i have added Machine Definition Import and Export.
To bring a new machine in to the active machine list
Click on "Edit" button next to machine list on FSWizard screen Machine Definition manager opens up and there you click on "Import" button.
A standard windows file-open dialog appears prompting you to select a file that contains the machine you wish to import.
After selecting a file and pressing OK, you will be asked to choose which machine you would like to import from the file. This is necessary as each file may contain many definitions.
To Export a machine or many to an outside file
(to share it with your friends, coworkers, or maybe even me)
Click on "Edit" button next to machine list on FSWizard screen Machine Definition manager opens up and there you click on "Export" button.
A dialog appears where you are prompted to choose which machines from your current list you would like to export.
After choosing your machines, click OK and select a file where you would like to save your machine list.
I know you guys have created your own machines for your self.
If you could use this new feature and send me your machines, that would be super sweet!
You can also upload them onto our support forums by creating a thread. If there will be enough interest i will create a forum sub-category where users would be able to share their machines with each other.
A little "Personal Touch" - i made a typo in the Export Machines window' title!
September 14, 2014, 4:09 pm by Eldar Gerfanov (Admin)
This weekend was very productive
I have finished work on floating license scheme and volunteers have begun testing it.
Licensing like that requires a lot of work on both the web side AND the client side. So a lot of things can go wrong and hopefully testing exposes all of the possible problems before a paying customer has the opportunity to face any.
Aside from cleanup here and there i have added the material search feature.
"Material" panel is now expandable and it is hiding a search field. When you type anything into that field, material list right above will filter out items that contain the text being searched. To clear search results user can just click the red x button to the right of the search field.
Here is how it looks:
You don't really need to click on the magnifying glass button as searing and selecting of material is done in real time as you type text.
In fact in many cases simply typing things like "D2" will select the material you need.
What's New:
Material Search Feature
Added several new machine profiles to the default machine list (When you install over existing installation, use machine import function to add them to your current machine list)
October 12, 2013, 11:32 am by Eldar Gerfanov (Admin)
Lately there have been a lot of really interesting HSM topics on PracticalMachinist forums.
In one of them a guy who owns his own resharpening business posted a video of his endmill milling a block of D2 hardened to over 60 RC. The forum topic is located here First try on D2 62Rc(video)
Here is his post so you know what we are talking about:
Quote:
In an effort to perfect our speeds and feeds while hardmilling, this is the first try. Its not right yet, but far from a failure. I apologize for the language at the end, but I do not edit my videos. The endmill was a reground garr VRX at .353 diameter. Parameters were 750 sfm, .018 radial, .300 axial and .004 ipt. The next run will be at 650 sfm, .006 ipt using a mist sprayer. Also, any small areas will be blocked off to be ran at lower speeds to allow cooling time for the cutter. Just a note for anyone using a Mag Fadal, The E-stop button is not quick enough, use feed hold. The endmill was badly worn on the corners, but not broken, and will be resharpened and used again.
In the ensuing discussion i posted my own take on how and why HSM works
Quote:
HSM works in many ways.
1) Reduced cutting time per edge per revolution allows it to cool down more. 2) Chip thinning allows to increase chipload (advancement per tooth per revolution) 3) Increased depth of cut combined with shallow radial positively affects deflection. Tool bends less as it is more rigid towards the tool holder. 4) Higher cutting speed actually reduces cutting forces as heat generated in the cutting zone makes it easier to shear off a layer of metal. Yet because the time of contact is so small, most of the heat is carried away with the chip. 5) Higher RPM also allows to get rid of hot chips faster thus further reducing heat transferred to the tool. 6) Higher feedrate actually reduces relative cutting speed. 7) At high axial engagements more than one flute is in contact with the workpiece at different points along the axis of the tool. This too helps combat vibrations and chatter. 8) You are using more of the tool than just its tip, so technically you can do more work with one tool before it gets dull. 9) lastly it looks cool as hell and is very impressive. Whenever we know visitors or bosses are coming we try to make sure some HSM is going on even if application does not merit that I am not sure if the air that is moved by the endmill is doing much, but i suspect he didn't mean exactly that.
You may freely reproduce information presented herein without any consent from me, provided you include link to this site. In case when i am not the copyright holder, you may want to contact proper owner of material. Anyway, they are freely available on the Internet. If you hold the copyright right for any of the materials on this site and want them removed, please contact me here