Second-hand metallizers & retrofitting

Here is a question that was posed any my reply along with some other generic comments about second-hand equipment and retrofitting.

The Question.

Hi,

I would like to know if its possible to retrofit an older vacuum metalizer ( made in the early 80’s) with a electron gun for the deposition onto glass / lenses.   If so have you come across any company’s that sell this equipment?

Regards

The answer.

The simple answer is ‘yes, it can be done’.  This is usually followed by a BUT.

Using an old metallizer to give you a cheap, large vessel with a pumpdown set can be cost effective if you get it cheap enough and you know the cost of the changes you want to do before you start.   In many instances the whole project does not get the costs estimated well and it ends up more expensive than buying new equipment or a readymade second-hand glass / lens coating machine.

Old machines that have seen a lot of work can have problems, or increased risk, of leaks due to fatigue failures of welds from the vacuum cycling.  So make sure it is leak-tight and can be pumped down to a low base pressure, if at all possible.

Using an old metallizer may mean the vacuum pumps are not sited well for getting good uniformity if you are doing reactive deposition.  This does depend on the type of process you are using. If you are removing the winding system and replacing it with a planetary motion or some similar complex moving jig to average out the deposition you may be able to average out any inherent non-uniformity from having non-uniform pumping.

The installation of electron beam guns is generally not a problem. There are plenty of suppliers of electron beam sources with single crucible, multiple crucible or rotating crucible designs.   It only requires space and sufficient leadthroughs to be able to install one or more into the system and if you are removing the standard resistance heated boats there will usually be plenty of space. 

If you want to deposit multilayer coatings there are some choices to make such as depositing from different guns or depositing from a single gun with multiple crucibles. So of this decision may be governed by the quantity of material that needs to be evaporated throughout a single run and it may be that a multi-crucible e-beam gun does not have the capacity unless the crucibles can also be fed.  If separate e-beam guns are used this again impacts the deposition uniformity.  Also the monitoring of each source and/or each deposited layer to make sure the total optical performance is delivered from the multilayer coating needs some careful thought.

Hence the design of your retrofit system will be critical to the success of your process and often the cost of correcting minor problems can tip the balance away from retrofitting an old system to buying either a new well proven system or a know second-hand system.

Companies such as Angstrom Sciences Inc,  Leybold Optics GmbH, and Soleras Ltd all offer re-built systems and so probably would help retrofit your machine. Alternatively there are usually smaller more local vacuum/engineering shops that would be capable of doing the job with suitable expert supervision from someone who understands the process you wish to end up with. 

General comments on retrofitting.

Retrofitting is often considered to extend the lifetime of a vacuum system but in some cases this has proven to be a false economy.  Upgrading the on-line monitoring system on a metallizer may give better information about the coating thickness but unless the control of the boat temperature and wire feed is upgraded too it may well be that all the upgrade does is to improve the information about how variable the process is.  If you then upgrade the control of power to the boats and the wire feed then for an old machine the cost of taking the machine out of production, the cost of the items that are often customised to fit that particular machine as well as the cost of recomissioning may be a significant proportion of buying a new machine.  When one considers that a new machine will also include a newer, more up-to-date winding system and any other developments that have taken place since the original machine was built it is likely that the increased productivity of the new machine would more than compensate for the difference in cost between the new machine and the old but refurbished machine.

Most retrofitting projects underestimate the effort, time, inconvenience and hence true cost.

Comments

[Roman das]

Dear sir,
Ineed second hand paper couting vacuum metalizer machine if avaible now please send the spcefication of your machine.

[shailesh mody]

dear dr. bishop,

Sir, interested in purchasing second hand aluminium metallizer, make GVE ltd, or any japanese or german make, request you to suggest some manufacturers either in europe or japan of high repute.

best regards,

shailesh mody

p.s.:- sir we want textile/packaging grade aluminium metallizer