Cost Savings When you Upgrade or Retrofit your CMM
Should you buy new or upgrade your existing CMM? Let's look at the pros and cons. No question a new purchase eliminates much of the uncertainty in the mind of the buyer; however, a professional upgrade has some benefits:
- One very important factor is that by upgrading, the CMM machine does not have to be moved from its current location; in some factories there just isn’t the proper space for moving machinery in and out.
- Amazingly, the average CMM has not changed much mechanically in the last thirty-five years. What have changed are software, controls and probing; and those can be replaced for a fraction of the price of buying a new CMM.
Things to consider when Retrofitting a Coordinate Measuring Machine
The first step in deciding whether to retrofit your existing CMM machine or to purchase new is to examine the costs involved. Normally the cost of a retrofit is less than 50% of the cost of a new one. Additional costs are also incurred when buying new, such as the costs of rigging and relocating or disposal of the old CMM. On a large machine, costs rapidly amount to many thousands of dollars.
Software
Software is the major reason most people upgrade their CMM. New products have the ability to read CAD, display results graphically and program offline using virtual simulation. Laser scanning is also a new parameter software must be capable of coordinating. Many of the best-known software packages have the ability to work with the existing CMM controller. PC-DMIS and Polyworks are recommended software products that interface with many controllers from different manufacturers, such as: Brown and Sharpe, Mitutoyo, Zeiss Wenzel and Sheffield.
In addition to their compatibility with CAD, these latest software releases will also be in compliance with the most current GD & T standards. North American and European GD & T standards have historically been revised every few years, forcing software developers to incorporate these revisions into new releases.
Software upgrades are very cost-effective, often less than $20,000, including a new PC and installation.
Controllers
Machines that are over twenty years old also require a controller replacement. One way to be sure of this requirement is to ask the manufacturer or the distributor of the product if replacement parts are available; if they are not available, then you have your answer.
Remember, it's better to upgrade and update on your terms rather than placing yourself in a position where your machine will be inoperable for several weeks or even months! It’s also easier to negotiate terms and price when you are not under pressure to have the machine operational.
A new controller on an older machine can offer many benefits, including simplified electronics and easier maintenance. It's a common fact that boards, etc., from older controllers generally cost more to replace than the price of the new controller alone. This is due to the fact that the boards need to be reconditioned or sourced from a used machine, since they are no longer manufactured.
In many cases, older controls exclusively handle touch trigger probes. If you are considering analogue scanning or laser scanning you will require a new control.
Probing
Probing is a much overlooked and potentially expensive part of a CMM machine upgrade.
Prior to choosing software or controls, it is wise to consider what multisensor you are planning to install on your coordinate measuring machine in the future.
Fixed Head to Robotic Head Upgrade
The most practical upgrade to your CMM machine, and the one that reduces programming time by up to 50%, is upgrading to a robotic head. Another benefit is increased throughput on the CMM, as a probe tip rack is not required to change orientation.
Touch Trigger
Touch probe systems are more robust, easier to program and give excellent accuracy on the position of features. Collisions are minimised due to the kinetic stylus module that will disengage upon impact. In fact, modular touch probes, such as the Renishaw TP20, allow the use of stylus change racks, making your CNC coordinate measuring machine run virtually automatically.
Scanning Probe
Consider some distinct scanning probe benefits:
- When looking at form or shape, scanning probes give better representation and accuracy due to their dynamic ability to collect thousands of points.
- Scanning probes are dual purpose; they can both scan and take individual points.
- Scanning probes can carry extra-length styli (usually above 400mm).
Following are some scanning probe drawbacks:
- The programming protocol is generally more elaborate than a touch probe, because there are more things to consider.
- Scanning probes generally cost several times more than a traditional touch probe or portable arm.
Laser Scanners
Laser scanners have the ability to connect to any CMM machine. They usually are connected to the Renishaw PH10M (Multiwire) Indexing head via the quick disconnect feature.
Laser probes, including the Leica laser tracker and the Romer laser scanner, collect hundreds of thousands of data points per second and are ideal for automatic scanning of components. Most scanners produce accuracy numbers in the 15 to 40 micron range with a laser line width of 50 to 100 mm. We currently recommend blue light scanners due to their ability to scan reflective surfaces, while giving the best accuracies.
Laser scanners work with the following software and controller packages:
- Software: PCDmis. Polyworks, Metrolog
- Controllers: Pantec Eagle Pro, Hexagon RC1, Renishaw UCC
Summary
It's clear to see that a professional CMM upgrade or retrofit is an extremely cost-effective way of giving you state-of-the-art measurement with a shop floor CMM.
Make sure to do your due diligence and have the retrofit company provide you with references of previous jobs. If you have any questions or seek advice, please contact us here at CMMXYZ.
